XP-Pen sent me their new Artist Pro 16 (Gen2): they were curious if I could get it to work under Gnu/Linux without their proprietary driver.
Result: after a long evening of trial and error, tweaking Digimend/X11/xsetwacom, almost everything works now. 
Of course, the deal is that if it works, I have to document it like I did with the Artist 24 Pro. So expect it soon™.
Btw, this one will stay on my desk: I had a serious crush on it while testing: super low latency & low parallax. 
@jimmac@mastodon.social@davidrevoy Wow, you're way more hardcore tweaker than I ever managed :)
@jimmac 
Haha, I realise that too. I'm taking a dangerous path. If I continue on the same path, you'll find me in a couple of years proposing MR for the kernel and libinput.