I am having this exact issue. Submitted a bug report as well.

Have they resolved it yet? I submitted a bug in Feedback Assistant and am attempting to have Apple Support look into it for me since it affects non-beta devices also.

Yep this is exactly what I have going on as well. Can't enable Find My on my Macs regardless of beta, etc. I do have an open ticket with "more than 10" as well. Hopefully they fix it soon. Thanks for posting this and keeping everyone else updated!

Mine is fixed as well! Hopefully yours will resolve soon Bvledford.