Thanks for your question and I am sorry to hear about that issue on the Mac. We officially support a new OS when it moves out of beta, or shortly after it moves. Technically speaking a beta version can change up to the last moment; so, for that reason, we do not support beta versions of a new OS. For that same reason, we tend invest our preparations when the changes seem to have settled and the beta seems to be moving to production.
I am sorry that we cannot currently be installed on the MacOS 12 beta and I am also sorry that Mac will not allow you to revert back to 11 without reformatting. I do want to applaud you for being any early adopter of a new OS as so many people are reluctant to update even after an official release.
I am more than happy to submit a triage of this issue to my developers for you and once again I do apologize for the hassle with the beta.