macOS on my laptop. I mainly care about battery life, I dislike having to carry a charger or be plugged into a wall. The M1 machines are unbeatable in this regard.
Linux on my desktop, specifically Ubuntu. No particular reason for using Ubuntu beyond that it’s free (as in beer) and fits my needs: casual gaming (as in no competitive online games with anti-cheat) and web browsing.
I think a handful of competitive online games require anti-cheat that doesn’t work on Linux. Afaik CoD and Valorant don’t work on Linux.