I cannot figure out what the issue is, but for some reason it crashes on launch. It's the kind of crash where it says "unexpected issue has occurred" but doesn't actually save any crash reports. I have the latest version of mixinbootstrap, the latest version of the mod, and it says on the issues page that a similar issue with optifine was solved.

I have a long list of mods installed so any known incompatibilites would be good to bring up first

Oh god, I will try to see if it can be fixed

mmmmmm not sure I can fix it tbh, but you can share the contents of the crash

that's just it, there are no contents
it just says "unexpected issue" and gives me error code 0 the second i launch it

are there any known incompatibilities that might be causing this? is optifine still a problem or was that fixed?

Yeah optifine and a couple other mods,
I can test it myself if you give the Optifine version and the OffHandCombat version

But from painful experience, if it crashes and its optifine it probably is hard to fix, and if it's not optifine it can't be fixed :<

i have the latest 1.16.5 version for both mods

The same thing. No crash log. 1.16.5. No optifine tho (sodium reforged)