I have it all working, and I did it the same way you mentioned above, also all that is needed in terminal to run is “sudo PoleMaster” by editing the bashrc file as mentioned on the QHY site...if you don’t do this it WILL NOT RECOGNISE THE CAMERA, the PM software will run, but will not see the camera, this is explained on the QHY site...
With this done it orks great in the QHY polemaster software but does have to be launched from terminal, however, it DOES NOT work in ekos at all, not sure why, also I have tried to created a desktop icon, but with no luck at all, but as I say from terminal, on QHY own PM software, it perfect..
So the solution you give above is perfect for getting the software to run, but the camera will not be recognised without another couple of steps... I realise as you do not have the PM camera it’s impossible for you to know this.