I have a very rough idea it is related to skinning (bugged hand tracking hands confirm that) although I have no idea what can be wrong there, is it layout of vertex data, shader itself (but then it would not compile, would just crash). I have to wait for have Quest 2 on my desk to fix this :(
Just wanted to chime in and say I'm having a very similar issue with the Quest 2 and weird model clipping issues outside of the menus, loading through the menus works great - all the environments are rendered fine - but my arms, guns, all enemies, and basically every other "object" does a weird z-fighting clipping thing and makes the objects nearly invisible and the game unplayable. :0 Hope you get your Quest 2 soon!