I'd suggest submitting a bug to Apple via Feedback Assistant. I also have this issue and submitted a bug with quite a bit of detail. I'm unable to enable Find My Mac on either of my Macs (one running 11.4, the other 12 beta 1) nor on my iPod touch (11.6), iPad Pro (15b1) or iPhone (15b1). Hopefully it's something they can fix on our accounts soon.
mattdelliott
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Yeah it’s been this way on all of my iOS and iPadOS devices.