You know, with well written character arcs this could be a really kickass sci-fi-fantasy novel. Where humanity essentially manages to transcend it’s limitations and becomes a group of posthuman entities straight out of Kurzweils wildest dreams, only to then be confronted by a extra-universal eldritch abomination that wants to destroy the universe because said eldritch abomination considers the post-humanity to be to powerfull, with the confrontation ending with an epic battle between post-humanity and the eldritch-abomination. The EA winning would be kind of a downer ending, but that is nothing good writing couldn’t fix.
Though I’m somewhat doubtfull whether high-level-transhumanism and actual deities can really exist within the same setting, given that transhumanism pretty much requieres philosophical materialism to be true, while god(s)/souls requiere it to be wrong.