I installed Steam according to these instructions. At the end I had to install the 32 Bit Open-GL libraries.
The following message appeared: Unsuitable Nvidia kernel module loaded
The Nvidia driver being installed (version 390.116) does not correspond to the currently loaded Nvidia kernel module (version 418.74).
The easiest way to fix this is to restart the computer.
I did this now and it works without any problems.
However, I was wondering if Debian now uses the 32-bit driver permanently. Maybe it just seems that way to me, but doesn't the 32-bit version have less performance and other disadvantages?
Can I somehow check which version is currently in use or control which version should be used?