Pro Display XDR smart features don't work

Hi! I just bought a Pro Display XDR second hand from somebody else.

The issue I have is that the "smart" features don't seem to be working properly. To be more specific:

• There is no brightness adjustment over Thunderbolt. I can change reference modes in Settings but the brightness slider is simply not there???

• There are no "Colour Profiles for this display" in Settings

• Auto-rotate does not work. I have a Pro Stand and rotating the monitor doesn't flip its resolution in macOS.
• Brightness adjustment using function keys doesn't work. They just adjust my attached MacBook's brightness.

I've tried four different Macs (MacBook Air M2, MacBook Pro M1 Pro x2, 2019 Intel iMac) and they are all the same.

The Firmware Version in System Information is weird. It's "55.2". Isn't the current Pro Display firmware supposed to be 4.2.37?

So what I was looking for some help for is:

• If anyone else has a Pro Display - can you tell me which firmware version is displayed in System Information for you?
• Is there a way I can force-reflash/reset the display?
• Has anyone ever seen anything similar?

I spoke to official Apple support and they were baffled. Though they did confirm they can see the Serial Number is real on their end. I did consider that it could somehow be a counterfeit product, but is anyone even out there cloning Pro Display? It's really heavy, it has the real machined lattice pattern on the back, it really is 6K, and HDR content looks incredible on it. I think it's a real device with a very confused firmware installation.

Thanks in advance!