Origen describes Marcion and others like as teachers of heresy, in part because of Marcion’s literal reading of the violence in texts like the conquest narrative.

But Marcion and Valentinus and Basilides and the other heretics with them, since they refuse to understand these things in a manner worthy of the Holy Spirit, “deviated from the faith and became devoted to many impieties,” bringing forth another God of the Law, both creator and judge of the world, who teaches a certain cruelty through these things that are written. For example, they are ordered to trample upon the necks of their enemies and to suspend from wood the kings of that land that they violently invade. And yet, if only my Lord Jesus the Son of God would grant that to me and order me to crush the spirit of fornication with my feet and trample upon the necks of the spirit of wrath and rage, to trample on the demon of avarice, to trample down boasting, to crush the spirit of arrogance with my feet, and, when I have done all these things, not to hang the most exalted of these exploits upon myself but upon his cross. Thereby I imitate Paul, who says, “the world is crucified to me,” and, that which we have already related above, “Not I, but the grace of God that is in me.” But if I deserve to act thus, I shall be blessed and what Jesus said to the ancients will also be said to me, “Go courageously and be strengthened; do not be afraid nor be awed by their appearance, because the Lord God has delivered all your enemies into your hands.” If we understand these things spiritually and manage wars of this type spiritually and if we drive out all those spiritual iniquities from heaven, then we shall be able at last to receive from Jesus as a share of the inheritance even those places and kingdoms that are the kingdoms of heaven, bestowed by our Lord and Savior Jesus Christ, “to whom is the glory and the dominion forever and ever. Amen!”

Homily on Josh. 10:20-26
There is an article by Katell Berthelot, “Philo of Alexandria and the Conquest of Canaan,” from “The Journal For The Study of Judaism” (Jan 2007) available from Brill or researchgate.net. The abstract says Philo used, in addition to allegory, silence on passages he didn’t like, playing with the meanings of the Greek, and indicating where Canaanites may have deserved it. “The Promise of the Land” from UC Press at publishing.cdlib.org, has a section, “Conception of the Conquest of the Land During the Second Temple Period” reviews revisions of the conquest narrative by Philo, Josephus, the Talmud, Jubilees, and lesser authorities. The basic ideas seem to be that the Israelites legally owned the land anyway, and the eviction of the Canaanites was voluntary, and such. Just in reading the Jacob/ Joseph section of Genesis last night, it seemed like these ideas of prior ownership of the land were being laid out there.