Ever since the new update, my GUI is broken. Toggling the Aristois menu with .toggle Menu results in a game crash, and pressing shift results in a grey screen. Also, all of my previous Appearance changes were reverted
I have optifine installed by the way, in case that's causing any of the issues.
Can you upload your crash log to https://paste.ee?
Try the command
.s menu blur_background falseand see if the UI opens normally.