Fingers curl up weirdly ingame

when i load into my avatar the fingers on it end up in a half bent position despite looking fine on blender and on unity, gestures do work but the tips of the fingers forever stay bent while the joints near the palm will bend normally with the gestures. ive been spending forever working on dumb issues like this on the avatar and this is the last thing i have to fix before the avatar is in a actually playable without looking stupid state

This video strikes me as relevant to your problem. The have an avatar with two finger problems, one is wrong bone mapping, but the other is fingertips bent incorrectly, and that second thing they fix in Unity by simply going into the “configure avatar” mode and manually rotating the fingers there.

So hopefully that second thing is the same as your problem.