Hi! I'm playing on minecraft version 1.19.4, Forge 45.1.0m and FancyMenu 2.14.9.

I overrode the world-loading menu with my own custom gui, in an attempt to (hopefully) not have to see the square loading symbol whilst loading into a world. All was good until I exited the world I was in, and attempted to reload and then my game crashed. I tried disabling the custom GUI by removing it's associated txt file, however the game still crashed. I went ahead and attached both my debug and latest logs, and I hope that provides enough info understand the issue, however if you need the files for my FancyMenu presets please just lmk!

Cheers!
debug.log
latest.log

Navigate to config/fancymenu/customization and delete all layouts for the world loading screen.

If that doesn't help, open the config/fancymenu/customizablemenus.txt file, remove the entry for the loading screen and restart the game.

btw: you can hide the world loading animation in the FancyMenu settings (click on the little FM icon in the top-left)