Topic can be closed.
I had a long discussion with ChatGPT and it seems there is really no solution since something changed in the background for Trixie which doesn't work anymore for this old game. Only possibility is to downgrade Mesa.
I found another solution for my case: In steam I switched to Proton compatibility mode for this game. Now it's running as emulated Windows version. CPU is burning.. but better than software rendering.
Statistics: Posted by Freeze — 2026-02-05 23:10