Have you heard of Distrobox?
You can run Debian and still get access to the AUR. I moved from Arch to Chimera Linux and but I still get a few things out of the AUR.
With Distrobox export, you can even add them into the app menu in KDE. So you do not even have to manually launch Distrobox to use them.
I moved my mother to Mint a few months ago. I have not had a single tech support call. She uses it daily. About a week in I asked her how it was going. She liked that printing worked more reliably and wished the scroll bars in Facebook were a bit thicker. Her printer used to show as offline sometimes in Windows but that issue has gone away under Mint. I was going to look for a theme with thicker scroll bars but she told me not to bother.
Granted she was a Firefox and Thunderbird user already so that helped with the transition.
Can you get Distrobox running on it. If so, put whatever distro you want on Distrobox and build whatever tools you need in there (including a totally different GCC or Clang toolchain).
If you want to scan for vulnerable systems online, here is a list of operating systems that will not be applying these “privilege escalation” fixes.
Have you heard of Distrobox?
Agreed.
Though if you get off the beaten path, you get things like system supervisor, system compiler, C library, and core utils.
But most Linux distros are systemd, GCC, Glibc, and GNU utils. Which brings us back to your list.
They are aiming for complete compatibility. They literally use the GNU test suite.
You are 90% of the way there.
Just keep your system up to date (update packages weekly maybe) and you will be fine. The system mostly manages itself.
I recommend installing both the current kernel and an LTS kernel. If you ever have a problem with a driver or a filesystem or something after an update, just boot into LTS and you are back up and running.
Unlike the Wine based stuff (Bottles, Winetricks), this runs actual Windows as a VM. So compatibility will be far better though performance will be worse.
Packages and package managers differ between distros. If you are changing distros, you should not try to preserve your package list. You will need to reinstall them.
However, you can often preserve your configurations and customizations by migrating the dot files in your home directory (or the entire home directory).
This is why many people put /home on its own partition. They can then wipe and reinstall the root partition while preserving /home.
You will get XFCE 4.20 at least. You can run Wayland now if you use Labwc as a compositor.
Even as a Wayland fan though, I would stay on Xorg for now if you are using XFCE.
What is outdated about Cinnamon?