How do I revert an AppleTV 4K from beta to stable/public? (Currently 14.5 beta)

AppleTV 4K upgraded to beta (14.5 / 18l5149j) - breaking Crave app entirely, and generally glitchy.

How do I revert to stable/public version?

This could be reverted with a USB cable for previous versions of the AppleTV, but there is no such port on the 4k.

All previous instructions said Settings->Profile... to revert. But this menu no longer exists.

Called support, nothing they can do except advise I take it to an Apple store.. who *may* be able to fix it.