Fiddler,
Thanks for interesting suggestion, but I think I figured most of it out.
I use Thunderbolt for second "touch" display. The problem was a buggy NVIDIA (video) driver. After full reinstall Thunderbolt accepted display. Apparently, USB-C (gen 2) does not show in Thunderbolt software "tray" as a connected device. What I was told, it has to be specifically Thunderbolt (r) device to "visually" show connection.

Go figure. As long as it works, good enough for me smile