Thanks Lea, you provide a stellar support here and I appreciate the responsiveness greatly!
Before I uninstalled Spacedesk (temporary I presume!) I hooked it up once again yesterday with no issues. Used it for a few hours, avoiding the Apple pencil 2 input method and just used is as a third monitor which is fine by itself.
I thought it could be nice for you to have a dxdiag full information file with this “virtual display” connected, see attached file. You don’t need to delete this as it contains no potentially sensitive information as far as I understand, could be good for reference to others to see if they experience similar issues.
It is a remarkable feat I must say, to be able to hook up an iPad Pro as client to a W10 machine using pen input on the iPad – over wifi involving a router no less! Of course a few ms of latency is expected but not very problematic, I was more surprised that it worked at all (until the host machine crashed).
Best of luck with this great software!