Hi,
v20.03 worked for me, I'm on Big Sur too.
It's buggy, but I was able to deal with it. The major PITA is not being able to use copy/paste inside CB - if I copied from a different app, I could paste it into CB, but when I copied text from a document in CB, I couldn't paste it, not even outside of CB.
But highlighted text drag and drop works...
I tried the latest nightly build, but it's crashing when I'm trying to adjust editor font properties.