I realized my first design had both aesthetic and functional problems.
So I made this version. The back now mimics the same curve as the headphones and they now have the ability to close like before.
Check out the complete headband replacement
Any infill and resolution should work.
I suggest at least 3 wall thickness for strength.
I printed it on its side with supports and that makes it strongest and less prone to separating in the middle due to constant stress.