Humanoid Gltf Avatar configuration on runtime!

I have a question regarding Avatar creation from script,
i’am close to have something, but at the end of my process, i have some carzy bones flips (or offsets).

i’m trying in runtime to configue a Gltf file of a Humanoid and setup to be a playable character !

i feel like i tried almost every solution…

do someone alraedy had this kind of problem and can helllllpppp meeee !

thx a lot !