Does canonical Luke either descends from Marcion’s Evangelion (the Schwegler Hypothesis)?
Jason BeDuhn argues for this in his The First New Testament: Marcion’s Scriptural Canon
-The Evangelion contains only one third of the “minor agreements” between Matthew and Luke. These are usually taken to be one of the biggest hurdles that the two-source hypothesis faces, (p.93).

The Evangelion does not include the John the Baptist or Temptation narratives. This means that, if it was original, any proposed Q material would lose its awkward narrative introduction and open directly on the Sermon on the Plain, being a more consistent saying gospel, (p.94-95).

Concerning the gospel of Thomas, the Evangelion (as far as we know) is missing none of the 19 parallels between Thomas and Luke. 15 are directly attested as to being in the Evangelion, with the other 4 being unattested whether they were part of the text. This suggests that Thomas could be dependent on the Evangelion for its sayings rather than (or at least just as easily as) Luke, assuming Thomas is dependent on Luke at all, (p.96).

With regard to the Parable of the Minas/Talents, an oft cited example of editorial fatigue where Luke could have been using Matthew, the Evangelion’s version of the Parable actually is missing many of the verses that theory stands on, including the ones that seem to show Luke using Josephus. This would imply that the Evangelion could predate, or at least be independent of Josephus, whereas Luke added information from Josephus to the Evangelion.
Alan Garrow’s work on the Synoptic problem, where he proposes that Matthew is dependent on Luke, and additionally proposes the Didache as a “Q”, with both gospels being dependent on it. https://www.alangarrow.com/mch.html
https://www.alangarrow.com/extantq.html
As BeDuhn puts it:

“Multiple gospels had already been written by Marcion’s time, and he almost certainly knew more than one of them. He may have commented negatively on some passages from the Gospel of Matthew in his only known composition, the Antitheses. But we do not know whether he knew of Matthew already when he selected a different gospel for his New Testament, or only learned of it afterward. […] Although Tertullian and other anti-Marcionite writers believed that Marcion had deliberately omitted Paul’s “Pastoral Letters” (1 Timothy, 2 Timothy, Titus), we now know that his Pauline collection contained the same ten letters circulating among many non-Marcionite churches of his time. […] Even the priority given to Paul’s letter to the Galatians in the Apostolikon, long explained as due to Marcion’s particular ideological interests, has now been shown to have occurred also in the ten-letter collection of Paul’s letters circulating among non-Marcionite Christians in Syria. In short, we need to break free from anachronistic judgments that Marcion “omitted” or “rearranged” texts relative to a later New Testament canon that did not yet exist in his time. As the first compiler of a New Testament, Marcion was at liberty to select and arrange texts as he chose, just as were later non-Marcionite Christian leaders when they compiled their own New Testament.” (p.28-29).
Additionally, supposing that Marcion had crafted the text of the Evangelion himself goes against one of the primary reasons some scholars have taken to “Marcion priority”. Namely, that Marcion’s text frequently undermined his own theology. This makes most sense if we understood Marcion to have been using a text already circulating at that time, again, similar to his use of the Pauline epistles. And of course, some of textual variants that Tertullian and Epiphanes accuse Marcion of making are actually well attested in a variety of early manuscripts we now have access to:

“Tertullian further charged that Marcion “mutilated” (caederet) those texts he did include in his New Testament—that is, that he altered them by excising passages that contradicted his views, or occasionally making slight changes in wording for the same pur- pose. More than a century later, Epiphanius similarly referred to Marcion having “excised” (parekopse) passages. Someone with Tertullian’s and Epiphanius’ presuppositions about the accuracy of their versions of these texts, and about Marcion’s motives as a “heretic,” would necessarily draw such an inference from the simple fact that Marcion’s texts were shorter than the versions of the works in question known to them. There was a well-known tradition of correcting corrupted manuscripts of the Iliad and other classic works of literature by excising what the editors regarded as inauthentic additions to the text, so it was easy to imagine that someone with Marcion’s concern with the “corruption” of the “gospel”—that is, the message of Jesus—would take up the editorial knife in a similar fashion. Yet Tertullian and Epiphanius found it easy—remarkably easy—to cite apparent inconsistencies in Marcion’s supposed editing: passages that were to be found in his texts even though they contradicted the very views he was busy promoting on the authority of these very texts. Either Marcion was an incredibly inept editor, as Tertullian sometimes suggested, or he had never undertaken such an ideological purge of these texts. […] In many cases, Tertullian and Epiphanius claim erroneously that the particular wording of the Evangelion or Apostolikon is Marcion’s invention, when in fact we find the same wording in catholic biblical manuscripts. The almost canonical status afforded the accusations made against Marcion, therefore, shows a remarkable lack of critical historical assessment among modern researchers.” (p.30-31)
Finally, what may be a sort of nail in the coffin argument from BeDuhn, is that the Evangelion of Marcion has a different set of harmonizations with the gospel of Matthew than canonical Luke has, as well as varying harmonizations with Matthew between Marcion’s gospel manuscripts. This suggests to BeDuhn that Marcion’s gospel text must have been undergoing textual variation well before Marcion had ever compiled his canon and split from the church at Rome, since a Marcionite who rejected the gospel of Matthew would never harmonize the Evangelion with Matthew’s gospel. He discusses this in a lengthy quote I’ll include below:
“Setting aside the difficult issue of omissions versus interpolations, what about the remaining content that Luke and the Evangelion have in common? It is here that perhaps decisive evidence comes forward. The Evangelion and Luke often switch places when it comes to harmonization to other gospels. Sometimes Luke appears to have a more independent text, while the Evangelion’s has been conformed to Matthew’s wording; at other times, the situation is reversed, and the Evangelion has the more independent text, and Luke’s shows harmonization to Matthew. This surprising evidence suggests that both texts were equally and independently subjected to harmonizing influence. It cannot be shown that either duplicates the secondary harmonizations of the other. In fact, from the evidence of the Evangelion we actually can identify harmonizations in Luke that we did not know before were harmonizations, because they are found in all of the surviving manuscripts of Luke—such as the “minor agreements” with Matthew, which some researchers guessed might be explained by textual harmonization, but could not prove it before now. So Marcion’s gospel text goes back to a period before most of the “minor agreements” got into the manuscript tradition of Luke. It might be argued that the different set of harmonizations found in the Evangelion simply goes back to the condition of the one manuscript of Luke used by Marcion to make his pared-down edition; and this would be plausible if the copies of the Evangelion known to Tertullian in third-century North Africa and to Epiphanius in fourth-century Cyprus had the same set of harmonizations derived from that single-source manuscript of Luke. But they do not.
“The testimony of Tertullian and Epiphanius to Marcion’s Evangelion conflicts in several verses where harmonization is a factor, showing that the Evangelion, like Luke, was influenced differently in distinct lines of transmission. This should not be so, if the standard patristic understanding of Marcion’s editorial activity were true. Harmonizing influence from other gospels on Marcion’s Evangelion is extremely unlikely after the establishment of a separate Marcionite Christian community which rejected all other gospels. Harmonization between gospels happens because scribes are exposed to another gospel text over and over again, and inadvertently (or sometimes deliberately) modify the text they are working on by their familiarity with the other one. It cannot happen when Marcionite scribes are copying the single gospel of their canon, away from all contact with the gospels of other kinds of Christians. So any harmonization to Matthew had to happen before Marcion made his edition. Then, if Marcion issued a definitive edition of his Evangelion by making significant editorial changes to a manuscript of Luke, any harmonization that had occurred in the transmission of the gospel up to that point would have been frozen in his edition, and this single set of harmonizations would have been passed on in copies made of it in an environment where it was not being read alongside of other gospels. In that scenario, even with other kinds of textual variation due to conscious or unconscious scribal changes, we should not see any variation in harmonization between the text known to Tertullian in the third century, and that known to Epiphanius in the fourth century. But we do.
“Previous researchers have suggested that Tertullian and Epiphanius must have introduced different harmonizations of the wording of the Evangelion unconsciously by their own familiarity with Matthew, rather than reliably recording what was in the Marcionite text in front of them. Yet where we can compare how Tertullian or Epiphanius quote the same verse elsewhere, we do not find the same particular harmonizations. Therefore, it cannot be demonstrated that they are responsible for the different wording they give ostensibly from the Marcionite text, and the latter’s varied readings begin to look more and more like the differences found between any two biblical manuscripts. But if different harmonizations were introduced into different manuscripts of the Evangelion, and if harmonizations can only have been introduced in a pre-Marcion environment where manuscripts of the gospel were still being copied by scribes familiar with other gospels, then Marcion could not have produced an original edition of the Evangelion from a single manuscript of Luke with a single set of harmonizations. He must have adopted an existing gospel text in multiple copies, or instructed his followers to acquire copies of the particular gospel he identified as authoritative.

“These points of textual evidence and historical circumstance, therefore, suggest that Marcion may not have produced a definitive edition of the Evangelion after all, but rather took up a gospel already in circulation in multiple copies that had seen varying degrees of harmonization to other gospels in their transmission up to that point in time. The process of canonizing this gospel for the Marcionite community involved simply giving it a stamp of approval, acquiring copies already in circulation, and making more copies from these multiple exemplars, so that their varying degrees of harmonization passed into the Marcionite textual tradition of the Evangelion. They continued to circulate in these slightly variant forms within that community, plucked from there in different manuscripts at different times by Tertullian and Epiphanius (as well as other polemicists). This conclusion from the textual evidence lends strong support to the Semler Hypothesis.” (p.88-90).
https://jesustweezers.home.blog/2019/01/18/the-case-against-luke-1-2/

This quote seems somewhat relevant:

The problem with that view is that Marcion does not call the gospel “Luke,” or indicate that its author was Luke or suggest that the author ever had anything to do with Paul. Instead, he simply calls it “the Gospel.” If the author’s association with Paul were the point, for Marcion, you would think that he would make the point when he referred to the Gospel. But he doesn’t. This has led a number of scholars (including me, now) to think that there was a different reason Marcion chose Luke’s Gospel as his Gospel (which he heavily edited to make it coincide more closely with his perspective, claiming that in fact he was simply getting it back to its pristine state before copyists messed it up by inserting passages that affirm the OT and the creator God, etc.).

—Bart Ehrman, 2013

Two key resources:

Roth, Dieter T. “Marcion’s Gospel and Luke: The History of Research in Current Debate.” Journal of Biblical Literature 127.3 (2008): 513–27.

Tyson, Joseph B. Marcion and Luke-Acts: A Defining Struggle. Columbia, SC: University of South Carolina Press, 2006.