I think WINE recommend an up to date distro due to rapidly changing stuff needing up to date software and kernel. I think Debian wouldn't be great for that. I'd personally recommend OpenSuse. Rolling, up to date and great with KDE. Good luck.

I have been running Debian sid for 23 years and I play all the games I want with minimal issues I couldn't work around. it may not be for everyone but works great for me. the debian wiki is great and using timeshift there is nothing so far I couldn't recover on.

I have used Nvidia in the past (RIP Evga) and now use AMD both worked great but AMD is easier since I don't have to do anything. also great tip the arch wiki is great for help as well.

Just need to rember it's not cut and paste there which you shouldn't do anyway but points you to the fix and just need to find the file or program equivalent for debian.

I haven't tried it, but I suppose you'll do just fine with debian sid. i.e edit /etc/apt/sources.list, swap $distro_nickname for sid, sudo apt update, sudo apt full-upgrade.

Depending on the games you wanna play it's probably safer to be somewhat closer to the bleeding edge than Debian would allow you to be. Nobara gets recommended so often because you get a good tradeoff between the newest updates and stability. Also KDE is their standard DE. PopOS is good if you wanna stay with apt, but comes with Gnome out of the box.

For Gaming Debian SID if you want Debian.