Personally, I had quite a lot of issues getting the nvidia drivers to work properly. Might have been an issue on my side of things don‘t know.
I really don‘t get their point regarding the negative impact. A platform should never be production critical. No one should rely on it for solving production issues. That is what enterprise support is for. I think that this is just an excuse for not being bothered to participate
Distro doesn’t really matter nowadays. You can get all desktop environments to work on most distros. Especially the big players like KDE, Gnome, Xfce have hundred distros they are shipped with by default. Most big distros have versions for each of the most popular desktop environments. Therefore, I would suggest that you look for the distro which fits your needs best and then install the desktop environment you want to work with afterwards, if there isn’t a flavor of your distro that ships with it already.
Does it fix the crash of Source games when opening the in-game overlay? Did anyone test this?