Windows 10 primarily, dual boot with Linux Mint.
I'd like to say I want to switch to maining Linux when Win10 goes EOL, but I make music with LMMS as a hobby and tried to switch that to Linux to get hooking multiple tracks to a single plugin to work...but the VST I wanted to use with that didn't work at all on Linux, so I have recent memory of compatibility issues with Linux. I'd probably already be maining Linux if I didn't game.