How exactly do I properly import a model to unity (and then upload to vrchat) when the armature looks like the one on the left? I keep getting models that are rigged like the left model and I have no idea how to work with that shit. I'm used to models that have rigs like the one on the right.

The problem is if I use CATS "fix model" button it (sometimes) converts it to the armature on the right, but it no longer works right, like the arms are fucked and things don't move correctly.