Years later, now with a mini-pc and a GTX 1070 eGPU, I'm happily playing The Witcher 2 in Mint 19.3. Weather it's the newer kernel, nvidia drivers or a combination of the two that did the trick, we'll never know.

It might also be the fact that I have also installed gstreamer-plugins-good:i386 along with its dependencies, a good to have package for 32bit native stuff or at least in conjunction with 32bit Wine anyway.

In retrospective, I'm going to give credit to dr.schliemann who was probably closest to the heart of the issue.