So you believe all the information we saw Trespasser was faked? And things like Andruil hunting Elves were simply made up?
It would not be the first time the information presented to us by the writers in game was misleading (examples: Chantry stuff, any elvhen lore pre-DA:I, deliberately translating Fen'Harel as the god of betrayal until revealing he was the god of rebellion, saying the Tevinter destroyed Arlathan but then revealing they did not, etc.) Yes, it would be a bit much to claim Solas is lying or that descriptions of the problems of the Evanuris are wrong, but it could be different than we think.
At the end of Tresspasser Solas reveals that the laws of physics pre-Veil were completely different, basically. That it was a different world, and we don't know what the Evanuris had planned that would have destroyed the world or why they killed Mythal. Solas is the only god thing to have destroyed the world once and wants to do so again. Their morality is based in different concepts, and I would not be surprised if things revealed about the Titans, the origin of the Taint, the plans of the Evanuris, the particulars of Mythal's death and the physics of a pre-Veil world (it is hinted that spirits are connected to the life span of the Elvhen, and that a living ancient elf could be made into a spirit/demon (the Forbidden Ones)), that they are not so simple as Solas simplified things in Tresspasser or how the limited Codexes we got in DAI led us to believe. Definitely they aren't Good but they probably aren't Evil, but then again, Solas thinks what they would do is worse than what he did, and he basically committed genocide the likes of which is hard to imagine.