It sounds like something is wonky with the communication from monitor to video graphics if it keeps going to reconfigure and switching resolutions or signal is dropping.
Linux is your main thing to be working with all this. PP doesn’t seem to have much to do with it since it hooks into the Linux touchscreen driver system.
I have gone as far as having to hack an HDMI cable and custom electronics to connect/disconnect an individual pin for a custom application totally unrelated to this one in terms of hardware hacking background…because there was nothing else available…
For this, I would try and known good HDMI cable and abandon ship if that didn’t fix it. I got my touchscreen for $100 shipped and only had to add one thing to startup to get the rotation for touch to work. You can look at my thread on what I bought and the one change I made for reference.
Viewsonic is an old company and respected but it sounds like you might have a lemon or this model isn’t fully compatible with something on your hardware and OS version…