No, Mark never described Jesus as God. In Raymond E. Browns Introduction to New Testament Christology, he lists passages in the Bible into three separate categories:

A.) Passages that seem to imply that the title “God” was not used for Jesus B.) Passages where the use of the title “God” for Jesus is dubious C.) Passages where Jesus is clearly called God

Brown lists several Markan passages in group A, (Mark 10:18, 13:32, 15:34) and no Markan passages in either of the other groups. In fact, in his conclusion, he states that there is nothing in the Synoptic Gospels that may indicate that Jesus was described as God. The only works that begin to equate Jesus was God are some of the later ones (The Johannine literature, 2 Peter, Hebrews). Aside from these, Brown puts a couple Pauline passages in the “dubious” category. The Son of God in the Roman World by Michael Peppard (2011), which basically shows how the author of Mark had kind of an adoptionist view of Jesus (I’m oversimplifying a bit). Peppard examples rhetoric about the Roman emperor as the “son of god” and reads Mark in that context, which lends itself to an idea more like God choosing a special human to give power and authority (Mark doesn’t have a miraculous birth story, Jesus’s origin isn’t eternal, it’s at his baptism).

Does Mark have Jesus as God?

First, it is super unlikely that Mark would have equated Jesus and YHWH for at least three reasons. (1) It would have been nearly impossible for a first century Jew to conceive such a thing. Asking the question in this way revels that it is being asked from a post-Nicene context. Christianity has given us a dichotomy between divine and human in which Jesus must either be equal to God or just be a human. In second temple Judaism there were more options than just this. Multiple documents and legends existed with angels of various levels, quasi-divinized saints like Moses or Abraham, and other exalted figures. In the earliest stages of Christianity, Jesus was probably put pretty high in this in-between category. (2) There is little to no evidence that Jesus was equated with YHWH. It’s true that the word “lord” was used of Jesus (1:3; 5:19; 11:3; 12:36, 37; 13:35) and that this word was the standard translation of YHWH in the LXX. But this alone doesn’t mean a whole lot. The word is still used in Mark for God (11:9; 12:11, 29, 30, 36; 13:20), and the word was used more popularly for Roman officials and emperors. Sometimes the word just means “sir” (7:28). It would be a mistake to read too much into this word. (3) There are passages where Mark seems to subordinate Jesus to God (10:18, 40; 13:32; 14:36; 15:34).
Second, the conversation about Mark’s christology has primarily focused around the titles of Jesus. Mark uses a few different titles for Jesus: Son of God (1:1, 11; 3:11; 9:7; 12:6; 14:61; 15:39), Son of Man (2:10, 28; 8:31, 38; 9:9, 12, 31; 10:33, 45; 13:26; 14:21, 41, 62), Christ (1:1; 8:29; 9:41; 12:35; 13:21; 14:61; 15:32), and Lord (already discussed). There are debates about each of these titles. “Son of God” is the most important of Mark’s titles. It provides a key structural component for the book, appearing at the beginning (1:1), in the middle (9:7), and at the end (15:39). It is the most concise answer to the main question of Mark’s christology, “Who is this?” (1:27; 4:41; 6:2-3, 14-16; 8:27ff; 9:7; 10:47-48; 14:61-62; 15:39). It becomes especially clear with Mark’s use of “beloved son” at three key points in the story, the baptism (1:11), the transfiguration (9:7), and the parable of the wicked tenants (12:1-12). Mark is crafting a narrative to show the identity, life, and rejection of God’s beloved Son.
“Son of Man” is super debated. Some argue that the title means nothing more than “a human being” while others think it is an exalted title based on Daniel 7. Mark’s use of the title points to the latter. The Son of Man gives new interpretation to the law (2:10, 28), forgives sin (2:10), acts as judge (8:38), and will come in the future (13:36; 14:62). It is the acceptance or rejection of the Son of Man that will determine one’s status in the eschaton (8:38). Mark’s use of “Son of Man” is especially tied to the suffering and rejection of his passion (8:31; 9:9, 12, 31; 10:33, 45; 14:21, 41). This might link Jesus with the suffering servant of second/third Isaiah. The point is that the Kingdom of God is brought about by the suffering Son of Man. “Christ” appears in two key locations, 1:1 and 8:29. The first establishes that Jesus is the promised Messiah, but the second, Peter’s confession, shows that one cannot too quickly understand what kind of Messiah Jesus will be. This brings us to consideration of the Messianic Secret.
Third, what an interpreter thinks about the Messianic secret will greatly impact how one views Mark’s christology. The classic articulation of the Messianic secret was in W. Wrede’s book The Messianic Secret in 1901 (English translation in 1971). Basically, there is a strange thing in Mark where Jesus keeps trying to keep his identity a secret. He tells the demons to be quiet (1:25, 34; 3:12). He forbids talking about his miracles (5:43; 7:36). And he tells the disciples to keep quiet (8:30; 9:9). Wrede argued that these texts were an embarrassing apologetic meant to explain why the disciples didn’t realize Jesus’ identity sooner. While some scholars still hold to this view, it is now a minority position. Most think that there is a rhetorical intent in the Messianic secret. The key text is 9:9, in which Jesus tells his disciples not to speak about the transfiguration until after his resurrection from the dead. The idea is that Jesus’ identity can only be truly understood by looking backwards on the whole story. Jesus’ messiahship is not just about powerful deeds, but it is about suffering and service (10:45) which is finally confirmed in the resurrection.
Fourth, the concept of authority is key for Mark’s christology. He uses the word “authority” 10 times (1:22, 27; 2:10; 3:15; 6:7; 11:28, 29, 33; 13:34) and all but one of those times are from his own hand and not from inherited tradition (2:10 is the exception). Jesus’ authority is seen in forgiving sins (2:10), making judgment about the Sabbath (2:27-28), criticizing his contemporaries (2:1-3:6), and calling people to be his followers (e.g., 1:16-20; 3:13-19; 6:6-13). When this is combined with the miracles of Jesus, a significant christological claim emerges. Mark is our main source for Jesus’ miracles. Most of the ones in Matthew and in Luke come from Mark. And Mark would have been the first to collect Jesus’ miracles and compose them into a narrative. The miracles make lofty claims about god, especially the ones in which Jesus demonstrates power over nature, which is a role reserved for God in the OT. These two ideas, authority and miracles, show that Jesus exists in a special relationship with God and has been given God’s authority. Regarding Mark’s quote of Isaiah more specifically, it is probably best to see some sort of unity of action between God and Jesus being implied. Preparing the way for Jesus, for YHWH, and for God’s Kingdom (1:3 should be read with 1:15), is the same because Jesus acts completely within God’s will for the establishment of God’s kingdom.