[NiHaoMike]

That's for the remote, which appears to use BLE. But it's the indoor unit that has the BLE chip, which he wants to get rid of. The outdoor unit communicates with the indoor unit over some unknown protocol.

I think the next step is to take a picture of the outdoor unit board where the indoor unit connects so we can see the coupling transformer or optoisolators and have an idea where to start. Hoping it's optoisolators (low frequency) since a high frequency link is going to be hard to reverse engineer even with a scope.