If possible it might help to have a couple demo PCs out so that they and try different desktop environments. Some might be more enthusiastic if they can not only play around with it when it’s up and running (and gives people something to do while your helping others) but also if the DE matches their “workflow better” it also gives you a chance to show them how to do common tasks. Maybe different demos have different “suites”, like here’s the gaming demo, here’s regular, productivity, etc
I agree with some of the other posts, I’d stick with 1 distro (whichever all the helpers are most comfortable with) so that you can speak confidently about it, and decrease the chances of something going wrong and you having to break out Google and the terminal. A DE is an easier choice to explain that different distros affecting and impacting things they can’t see. Especially if you might have to provide tech support during the beginning. Maybe just say a throw away line or 2 about there being different distros, just like there’s different kinds of cheese. Still same thing at its core, just different options.
I also recommend a couple spare external hard drives for them to back up their files.
I’d maybe do just a brief overview at the beginning. And go more in depth afterwards so they don’t get overloaded.
OP, I had a similar issue, and I had to blow way the wine prefix.
Someone else will have to chime in, but I believe it’s the “compat data” folder, but be careful because some games like to keep saves in there.
After you do that, as someone else mentioned, try GE-Proton.
Also I’m not familiar with your card, if it is older, I believe there is a certain gen where they stopped adding older cards to the newer drivers. A lot of the distros you mentioned are new, maybe roll the dice and if you feel up for it try Debian. If games boot, the. You either have to grab the open source driver or use an older version.
Also for the future (after you’re up and running) you shouldn’t skip the shaders. Steam crowd sources them from similar configs and build, and vulkan can generate them before playing so that game play is smoother. Direct 12 trys to generate shaders during game play, which results in stuttering.