The mod (1.20.1 as far as I know, but probably later and earlier versions) is incompatible with the SkinShuffle mod. The game crashes once the main menu screen is loaded. SkinShuffle and Wildfire's Female Gender mod are the only two mods installed.

The crash log is posted here.

Here is a video representing the problem:
https://github.com/WildfireRomeo/WildfireFemaleGenderMod/assets/83091369/773a4ee1-9e7d-4a23-b4cd-a6a4b57f9245