[21:28:53] [Render thread/INFO]: Caught error loading resourcepacks, removing all selected resourcepacks java.util.concurrent.CompletionException: net.minecraft.class_151: Non [a-z0-9/._-] character in path of location: minecraft:optifine/cit/itembound/!wip/skulls/bob.properties

The cit pack I'm using works fine using optifine, however cit resewn will refuse to load it, because your regex appears to not match what optifine uses.

I think it should be [a-zA-Z/._-\\!]?

I'm not doing any regex, it's vanilla that stops you from using special characters in paths. This is standard pack formatting for both resourcepacks and datapacks and optifine is just not implemented properly.

Read the FAQ/config for a fix.
https://citresewn.readthedocs.io/usage/help/

Alrighty
I thought it would have been your mod since it worked on optifine :/