if i use the mod in combination with skin swapper the loading screen is in a non ending loop

Skinswapper overwrites a mixen, causing the client to get stuck. It's not compatible.

is there a alternative to eitehr skin swapper or firstpersonmodel?

Not that I know. This is something skin swapper can fix, by removing that unused(unnecessary) mixin.

ok tysm ill open an issue on the skin swapper site