Have you tried the new OpenCore 0.7.5 EFI? I've enabled this for Monterey only, but can do so for Big Sur as well if there's a need.
Installed 0.7.5, and still no go on 12.0.1. Is there another step, or a pref file I need to purge?
Product ID: 0xf901
Vendor ID: 0x04b4 (Cypress Semiconductor)
Serial Number: 0016A4536363
Speed: Up to 12 Mb/s
Manufacturer: Cypress Semi
Location ID: 0x14500000 / 14
Current Available (mA): 500
Extra Operating Current (mA): 0
Firmware Version: v0 c0
Product ID: 0x0001
Supported services: 0x382039 < HFP AVRCP A2DP HID Braille AACP GATT Serial >
Vendor ID: 0x004C (Apple)