Which Qubes dom0 repo is considered the most stable? In my experience, the qubes-dom0-current-testing
is actually more stable than the “stable” repo. Is this because updates and bug fixes happen faster in this
repo? Does the QubesOS documentation reflect this?
I’ve been using the Qubes testing repo in dom0 and all my qubes for years, and it’s pretty stable. There’s some occasional bug, but most of the time it’s fine. I wouldn’t recommend it for regular users as it requires extensive troubleshooting to fix issues when they happen.
Yes, here:
In my experiece, the qubes-dom0-stable repository is actually more unstable than the testing repo. I wonder if that’s because the testing repo is update more frequently.
When using the stable repo the hypervisor kept crashing, and when it was switched to the current-testing repo the crashing stopped.
Newer hardware is better supported in newer kernels but newer kernel versions could contain more bugs and be less stable than older kernels in general.
I guess time will tell if that statement ends up being true in my case 
There is something either buggy or malicious in the Fedora Project graphics libraries. …
It depends on how you define “stable.” It sounds like you are using “stable” to mean something like “problem-free.” That is different from the traditional software development sense of “stable,” which refers to software that has gone through a testing procedure and that cannot be changed without going through testing again. (There can also be more complex policies regarding version freezes and backports.) This is designed to minimize the possibility of regressions (things that used to work that no longer work due purely to changes in the software while the rest of the system remains the same).
The idea of having a “stable” system, in this sense, is that once the system is working correctly, merely installing stable updates should never break it. This is different from trying to get the system to work correctly in the first place, which faster and newer updates can sometimes make easier, especially on newer hardware.
I don’t think the source of the issue is with QubesOS code repos, in my opinion it is Fedora Project code, which is considered trusted security-critical code. It is an Intel graphics driver library most likely, or X Window server software (Zephyr). It keeps crashing the entire hypervisor (xen). Again, this is when SYS-GUI is in use.