I have a Quest project that I'm now porting to Pico Neo 3 too. Unfortunately there doesn't seem to be any usable AndroidManifest either in the SDK or in the Documentation so I'm trying with what I have. The game appears in Unknown sources, but when I launch it, it only shows a black screen then it goes back to the OS.
I think the current documentation is missing a number of information about project setup. Any help is appreciated.