Making a "COREMOD" for another mod (1.16.5)?

[SleepyCatGuy]

So I am trying to combine FTBChunks and Xaeros Maps together My problem is I need to "disable" some functionality (i.e. keybinds so you cant open up the map and others) but to do this i need to either re-write that Method(perferebly. So i can do other stuff aswell) or go through forge. I essentially need to create a "COREMOD" for these mods. my (unclear, brain storming) thoughts on how to go about this are:

 - disable the mods and rebuild them with subclassing and AT.

 - disable the keybinds through forge and use reflection to call certain functions. I feel like this could be extremely buggy because I have no control over the mod except for calling Methods

 - just overwrite certain Methods with some black magic (pretty much the first one just no subclassing and no disabling the mods (AT?)... pretty sure this is impossible, like black magic does not exist)                                                                                             yet

 

I think i answered myself with the first one but either way hoping one of you can give me some suggestions on how I should proceed.