Hi All,
I was able to pair both an SN30 Pro+ and a Pro 2 without issue - I’m not sure what the issue may be that you’re all facing 
The procedure I followed was:
- Grab a preloaded RetroPie SD card from our shelf stock
- Boot it up on a Pi 4 8GB
- Setup a USB keyboard
- Open up the Bluetooth configuration
- Press and Hold Start + Y (Switch mode) and then immediately hit Enter on "Register and Connect to Bluetooth Device
- Quickly tap down the manual to select Pro Controller, then hit Enter
- Hit enter again on the first option - “DisplayYesNo”
- Taken back to the Bluetooth Configuration main menu.
- Controller is paired and immediately works to move around in the bluetooth configuration menu with the analogue sticks and dpad
Possible things that may make a difference:
- I’ve got my controller right next to my Pi to ensure a good signal while pairing
- I’m keeping an eye on my controller to make sure it doesn’t power down while searching for a connection/bluetooth devices
- My controller batteries are fully charged
