>>304781709
The arms are bent because your real life arms aren't reaching the end of your avatar's arms. I think this is often because anime avatars have big heads, and people line up their viewballs with their eyes, thus your RL shoulders are probably higher than your avatar's or at the very least not matching up
An easy way to resolve this is simply to make the in game height shorter so the game thinks your arms are shorter
As far as the tiptoe thing goes, an easy fix to that is simply to unmap the toe bones in the rig editor