I had this exact issue today on my 2019 Vantura Mac Pro - as a matter of fact I found this thread by searching on the output of system_profiler SPBluetoothDataType from the terminal:
Bluetooth Controller:
Address: NULL
State: Off
Chipset: BCM_4350C2
Discoverable: Off
Firmware Version: v0 c0
Product ID: 0x0001
Supported services: 0x382039 < HFP AVRCP A2DP HID Braille AACP GATT Serial >
Transport: UART
Vendor ID: 0x004C (Apple)
I would try to turn on bluetooth from the top menu - hit the oval switch and it would look like it was turned on but when looking at the blutooth settings the icon would just spin and there where no devices present. Of note when I used opt shift and then clicked on Bluetooth settings it would indicate the bluetooth was not discoverable which would make sense, since the service was not stated. I also tried sudo pkill bluetoothd with a restart and sudo pkill bluetooth with a restart. The only thinbg this achieved as setting the bluetooth switch back to off. Also of note this whole time the bluetooth icon in the top menu had a left to right slash through it incidating it was disfucntional. Nothing suggested online made any difference for correcting this situation. Bluetooth simply was not functional and could not be turned on. I even went as far as unplgging all (and I have many - above 20 -- as this is part of a music studio) USB devices (which is complete garbage in my opinion but I tried it along with multiple reboots). One thing that might have brought this on was I was listening to Airpod Pros outside and a couple times I walked beyond the listening range. I found all this out about 10 minutes before a video meeting and found that my Airpor Pros would not connect and my Bluetooth was non functional.
Here is what I had to do for the fix. Reboot the Mac Pro Ventura into recovery mode with cmd r held down during reboot. then chose the reinstallOS into the original target disk. This is very poorly explained online - it's called a step by step guide -> use it Apple, it is too easy to completely hork your system by making the wrong choice during the process. But doing this reinstalled Ventura into the target disk without changing any settings or uninstalling/overwriting any applications and all the machine settings were intact. It took aobut an hour give or take. Another important point when doing this procedure you need to have a keyboard and that is directly connected to the machine. When the Ventura OS reinstall was complete the bluetooth sedrvice fired right up and it could discover my Airpod Pros as well as my smart/magic keyboard and tracker. Thisis now the current output of system_profiler SPBluetoothDataType from the terminal:
Bluetooth Controller:
Address: F8:FF:C2:0C:48:45
State: On
Chipset: BCM_4364B3
Discoverable: On
Firmware Version: v91 c4210
Supported services: 0x382039 < HFP AVRCP A2DP HID Braille AACP GATT SerialPort >
Transport: UART
Vendor ID: 0x004C (Apple)
Not Connected:
EXPC02G41Q3MD6V:
Address: 88:66:5A:52:3C:AD
Michael’s AirPods Pro:
Address: A0:A3:09:23:DD:98
Vendor ID: 0x004C
Product ID: 0x200E
Case Version: 1.4.0
Firmware Version: 6A321
Minor Type: Headphones
Serial Number: GX8GNWUN1059
Serial Number (Left): GX7GMGUU0C6K
Serial Number (Right): GXDGN96G0C6J
This was the only way I could find to restore the Bluetooth service without a complete rebuild (this was close enough) but thankfully I didn't have to reinstall 156 apps and reconfigure the machine post a completely fresh install. the machine was exaclty the same configured with three huge screens and all logins and settings intact. The only thing I had to do was pair my Airpod Pros again. I would cross reference this outlined process with other references online for OS recovery it is tricky and nerve wracking requires patience. I have done rebuilds many, many times so I am familiar with the process. Start with an older cheese grater mac pro if you have to to get a feel for it. I would not reccomend this for a first timer unless you are willing to completely reinstall your OS from scratch and reinstall all your apps if you make a mistake. But I will tell you that it worked and restored the Bluetooth service to functionallity (running) when nothing else would work.
