Currently Clover does not support Big Sur; at least not for the installer, which means you'll have to convert to Opencore. It's still new and might require a lot of testing to get it working.
Big Sur is still in beta so if you're not in a hurry, it's best to just wait.
Let everyone else do all the leg work 1st, so when the release version is out, you'll have a better chance of getting it to work.