Theres a lot of mods that bepinex offers that players enjoy, like anticheat and other things that have to be handled client sided. Could Umod add bepinex support? (What I mean by this is when you try to use umod and bepinex on the same server umod breaks and wont load any umod plugins, but bepinex wont break)

I think umod would get a lot more users for valheim and more authors making plugins for umod, as far as I know when bepinex is used on a server that umod is installed on, umod's compiler breaks.

They are separate mod platforms, there isn't really a sane way to support another.

There is very little that is available for bepinex that isn't already possible via uMod or can be made as a plugin. Most of what you see for bepinex is for clients, not the server. Event the "anti-cheat" isn't really much of anything when used server-side.