Unfortunately very high, especially with modern systems using “trusted platform module” (TPM) hardware that can tell the software exactly what’s running, at a higher privilege level than the OS

The problem is that modern DRM/anti-cheat often works at the kernel level, or by scanning the entire filesystem and running processes. They don’t work on linux by design, so the main route to compatibility is showing that there are enough people gaming on linux that they should seek other options for DRM and anti-cheat

I think the issue of gaming on linux hasn’t been performance for a while now (native and wine/proton performance can often beat windows) but compatibility - some games still can’t run on linux due to DRM, anti-cheat, etc. Things are gradually improving but I think that’s the main barrier for the time being