When running the anti-matter chemistry modpack and introducing Cubic Chunks into it-
it causes the main menu to crash due to modularUI.
I have no idea how these two could possibly have issues but removing ModularUI just fixes it.

https://www.curseforge.com/minecraft/modpacks/antimatter-chemistry
https://www.curseforge.com/minecraft/mc-mods/modularui

its worth noting that the ModularUI api is used only for the scrollwheel sorting mod included in the modpack
https://www.curseforge.com/minecraft/mc-mods/inventory-bogo-sorter

Okay I recreated the issue with a minimal forge environment.
That means just forge 1.12.2, modularUI, mixinbooter, VoidislandControl, and CubicChunks/CubicWorldGen.

Crashes in menu as expected

crash-2023-01-16_22.49.44-client.txt
debug.log
latest.log

think this should be the correct logs

Can you provide a crash log?

Here

crash-2023-01-16_20.27.52-client.txt
crash-2023-01-16_20.22.26-client.txt

log.gz? I apologize I tried googling it but I didn't find the location of just debug.log, if you could point me to the right folder that'd be great
2023-01-16-6.log.gz

I would need to see the whole debug.log file. This is likely yet another weird mod interaction breaking Mixin on LaunchWrapper because coremods do weird things

It should be in the logs folder. If it isn't there, try a different launcher. Latest.log should also be there, that may also provide some useful information.

I tried downloading CurseForge but that doesn't vibe with my system apparently so I cannot use that. Can you please recommend me some other modpack launchers compatible with CurseForge modpacks?

I don't see anything obviously wrong here aside of the ModularUI Mixin configs just not being recognized at all for no apparent reason. Can you try without CubicWorldGen? I feel like the issue is MixinBooter but i don't have no idea what it actually does. It's a really strange way to use mixin that isn't needed for anything afaik.

A different mod that idea mixin the same way as CC is MalisosCore. Can you try those 2 mods with just MalisosCore instead of CC/CWG? That should show whether the issue is MixonBooter breaking when another regular Mixin mod is present.

I gave it a try and the crash doesn't occur when CubicWorldGen is removed.
The crash doesn't occur when MalisisCore is introduced.

The crash occurs specifically with just CubicWorldGen and ModularUI.

Interesting. Still almost definitely an issue with MixinBooter. But that will be interesting to debug.