Currently Windows 10, but I've been trialling Bazzite as a daily for the past couple of months and will most likely switch to that permanently* once Windows 10 is taken out back and shot.
It works perfectly for 99% of stuff; there are a few programs which don't have a working Linux version, but I'm hoping that the rise of SteamOS coupled with the mess that is Windows 11 compatibility is going to result in Linux gaming become more mainstream and developers actually making Linux versions of their software. Software compatibility is certainly going to figure into my purchasing decisions for any future hardware!
I have Windows 11 on my work laptop and it does my head in, some really bizarre design decisions around hiding settings away and generally making it as difficult as possible to do anything that's not dumbed down for your average TikTok drone.
I'm sure it's fine for the majority of people who just want to check Facebook/eBay/write a few Word docs. & Excel spreadsheets, but for me at least it feels less like an OS and more an app store masquerading as one.
Edit: today is a perfect example of why 11 is an utter pile of excrement, a putrescent shower of filth, expelled from the bowels of Satan himself. Just logged on to my work laptop to find it's decided to reboot overnight, losing a load of work and things I had open (not the first time). So that's about an hour wasted this morning. GG.
* I'll keep a dual boot of Windows for the odd piece do software which just refuses to work