Any idea where these hundreds of unused Docker volumes came from?

Yes, this happens automatically for me when I launch games. I don't remember doing anything special to set it up (Kubuntu with nVidia drivers on X11). I do mostly game in true full screen though, not "full screened window"

Amazing project, well done HeavyBell!

It's hard to write and hard to read. The forced joining of every single letter in a word quicky makes it unintelligible unless your handwriting is perfect or you write very slowly

The Nvidia driver has very good performance, and for most usecases it's.... Fine. But it does bring extra hoops and issues. There's a reason many distros have started to ship the "normal ISO" and the "nVidia ISO".

The nVidia driver also uses kernel modules, which can interfere with secure boot.

And many modern features are developed for Wayland-only: Mixed refresh rate, mixed fractional scaling, HDR etc. And nVidia is behind on Wayland support, since they only recently decided to cave on and use the same pipeline as AMD/Intel instead of their own.

Sounds like you've been very unlucky. Even the open-source Nvidia driver should work out of the box and look OK. Performance is ass, but it's good enough for a usable desktop experience (usable enough to install the proprietary nVidia driver, which at least on Ubuntu's are just a few clicks in the GUI)

Instead of going Fedora, try PopOS. PopOS has a special ISO for nVidia graphics. Trying to "install" the Nvidia driver yourself on a live USB boot is not the way to go. I doubt it's even possible.

I've been on (K)Ubuntu, and XBox controllers have literally just been plug and play. I could even use the KDE game controller settings page to compensate for the drift in my left joystick.

Another option is Bazzite, which is a version of Fedora Immutable ("Silverblue") that comes with all the bells and whistles for gaming, including Nvidia drivers. However the immutable part may or may not be to your taste.

No, not necessarily. Wine programs usually have access to your home directory as a Windows drive (X: or Z: or similar). So do be careful

Assuming you've tried Gimp, Krita, Inkscape, Blender, Darktable, what your deal-breakers for these open source tool? Any particular missing features?

Yeah fingers crossed, I also have one one order, but worried about the PSU

It sucks you had those issues, but it's good to hear the support team does actually provide support