I also need to echo the same concerns.
I have a 2018 Mac mini as well. After the 10.15.1 update, I get "Bluetooth: Not Available" and no hardware shows in System Report.
I have tried:
- SMC Reset
- NVRAM Reset
- Full Catalina Reinstall
- Delete all Bluetooth-related .plist files
- Unplugging EVERYTHING and leaving it off for several hours
- Ran the internal diagnostics (D-key boot up). No problems found.
My inclination is that a firmware update in 10.15.1 has bricked the Bluetooth controller, and perhaps even those who have had their logic board replaced have the same result occurring when Catalina boots back up. Power supply problems? Highly, highly improbable.
This really does seem like a recent update that could possibly be bricking perhaps a certain batch hardware. Not good.
For those with similar problems, I got my Mac mini in December of last year. It's the 3.2 GHz 6-Core i7 with a 1TB SSD. I have upgraded the RAM after the fact.
All that's left to try for me is roll back to an older backup... This seems like a nasty problem if it is what it sounds like.
One would hope they'd jump on this quick and perhaps fix it with a subsequent update, but this feels to me like the kind of thing Apple gets dodgy about and denies until there's some uproar. I would suggest everyone with the problem contact Apple ASAP.
Has anyone else in this thread with this problem found resolution yet?