Does anyone of you have an issue with the QHYCCD connection? I am having this issue on my QHY168C recently. I can confirm that it is not caused by cable because I manage to connect my QHY168C via NINA and SGpro from windows.
Skywatcher AZEQ5GT using EQMod
Pentax 100 SDUFII for the light
QHY168C mains with ASI120MC on guidescope
SX filter wheel
Robofocus focusers with DIY Moonlite compatible controller
RPI 4B, Stellarmate & Astroberry
If you can open a terminal window on the Raspberry pi and enter tail -f /var/log/syslog and then connect your camera you can see if it successfully connects to the RPI4. I have had issues with a USB3.0 hub not having enough power to run the camera. A warning will show up in the terminal window if that's the case.
I don't think the RPI4 ports are powerful enough to run the QHY coldmos cameras.