I have the same issue. We are using Kstars on Windows and an Raspi with the Kstars/ekos system.
We are currently testing the hardware how it works and just fiddling into all the stuff.
Currently we are testing it with a Fuji X-T3. After finally fiddling out how the Camera can be switched to Tethering mode. After that it was possible to not just connect to the camera but also make a preview picture. But then a error came up. Sorry, that I donĀ“t have the exact phrase at the moment but it was like "GGGG - wrong bayernpattern". I have read in another Thread that the raspberry is not yet able to handl X-Trans Chips.