Kubuntu 20.04 Lutris main window showing "no games found"

I had done some hours/days in configuring a number of games around Dec 20/21 and all went fine, so I could play all the games (for ex Guild Wars 1+2, battlenet with sc2, epic-launcher, Pharao, Rage, rox, sacred2, diggles etc. - nearly all done manually as already installed under windows).

Now I started Lutris today after a longer time (after several Kubuntu-System and other updates over the past 4-5 weeks).
As I found out the whole Lutris window is empty (no list left for win, steam etc.) - only showing “Kein Spiel gefunden” (“No game found”).
There are 29 yml files in the games folder of .config/lutris.
I get a “No cores found” line in the console and some more other lines about Versions of Lutris, CPU, GPU etc.
So basically I have no clue (as I am not a programmer, sort of beginner in Linux, mainly win-user) and no idea how to fix this.
I’m running Kernel 5.4.0-81-generic with KDE Plasma 5.18.5 on an intel 4790k with 24Gig.

lutris -d output here:

Help would be very appreciated. :slight_smile: