sado1

My personal workaround is a smartphone book case with a spot for the debit card.

Would be a good guess, but Gordon mentioned that in his latest try, he installed Arch-based EndeavourOS instead of Mint.

I looked through the posts.
Explanation of the issue: the userspace implementation of OpenGL for Xorg, called GLX,does not work, maybe it isn’t loaded. From what I see, /usr/lib/nvidia/xorg/libglx.so is no longer included in nvidia-utils package, the new name for it is probably libglxserver_nvidia.so

Did you have any lines with (EE) in Xorg.0.log?
Do you see if this log says, if libglxserver_nvidia.so was loaded correctly?
Wouldn’t hurt to check, if nvidia kernel module is loaded: lsmod | grep nvidia
Maybe reinstallation of nvidia-utils package could help, although I am pretty sure this was done already when you removed and added nVidia driver again.

Feel free to PM me, whenever you give it another go, even if it’s half a year from now :) I’ll do my best to provide you some advice.
(‘nv’ is an old driver for old nVidia cards, you shouldn’t look in that direction, it’s normal that it doesn’t load, if nvidia driver does)

• KeepassXC should just work, if the browser’s key was added to your KDBX database successfully. Other than that, I am surprised.
• Yup, the motherboard clock thingy is a consequence of Windows storing local time, vs Linux storing UTC. It’s a minor thing to fix in any of these systems, though.
• Shortcuts thingy - never had a problem, although I did have a problem with KDE’s keyboard shortcuts to run a program, which may be related workflow and maybe both were/are broken.
• KDE Connect is surprising, as at least for me it worked flawlessly
• The reboot thingy must be related to Linux Mint. I saw similar thing in EndeavourOS. One nice thing that some distributions implemented, is the ability to apply updates when you poweroff - from my point of view it’s a less annoying solution than what you describe.
• I can’t comment on the ‘cherry on top’ one without more details.
  I had a somewhat similar issue on my work laptop a short while ago, when I installed a program, which included a bugged XML settings file, then ran system update. When the updater tried to rebuild some caches (related to ie. icons, MIME etc.), some programs which use these caches simply stopped working. Reinstalling all packages with apt was the only thing that helped, to this day I do not even know all of the parts of my system that were broken.
  But this was one of these issues that happen once per 5 years, and leave you scratching your head and asking “what the hell is going on here?”. The difference from Windows is that in Linux, you can have a high understanding of system’s internal modular components (at the cost of time needed to learn it), and regular system issues can be identified after a few minutes of Googling.

I’m as skeptical as you are, but at least they automatically preinstall a few useful gaming apps by default, ie. LatencyFlex.