It's not so much that I believe it 'by default'. Rather, when I've examined the historical case for the resurrection, the arguments that it really happened seem stronger than the arguments that it was a hoax, or a mass hallucination, or that he fainted etc.

PostmarketOS have a wiki page for it. Looks like it's tethered only, and pretty limited.

I'd suggest maybe wait for 4.1. I just started playing with 4, and hit a bug where Godot will hard crash whenever you try to view the Terrains tab if you've created terrain sets, used them in your scene, then deleted the terrain sets.