This is a rather naive understanding of how logging is done in practice. The reality is that developers often don't know (and maybe can't know) just how severe an odd condition may be in practice.
Unfortunately, neither do I. Though seemingly unrelated journal-visible issues are quite often indeed independent, sometimes unexpected interactions or common root causes occur.
If there is still an actual problem on this machine (not just warning messages), please open *1* bug report that describes the actual problem and the log messages.
If under *actual* you mean *user-disturbing* (“error, flaw or fault in the design, development, or operation of computer software that causes it to produce an incorrect or unexpected result, or to behave in unintended ways”, a definition from Wikipedia), I've got none for the kernel because the kernel is not visible (nor should it be visible) to users directly. The only (sometimes reproducible) full lock-up (SysRq doesn't seem to work) I saw myself, which might concern the kernel, happened when epiphany-browser loads Google maps directly or embedded into a different Web site; I plan to submit a bug report.
As for other high-level problems which are already posted, there are at least two (and more are likely to come).
One of them, already resolved recently (though the root cause is still unknown, the intermediate problem is gone) is #1041014. If I had to state the *actual* problem there, it would have been „the machine doesn't boot properly, the screen is black, the keyboard doesn't seem to respond“; such a description would've probably been considered *actual* but pretty useless to the maintainers. Even if it would have been useful to you, then only in the sense that a failure to start a graphical user interface should not prevent text logins from visibly showing up on Ctrl + Alt + F1 … Ctrl + Alt + F6 and that error codes (instead of "ERRNO" and "exit-code") from failed spawns by systemd should be printed.
As another big problem on another machine, cf. #1040497. A next step in debugging this could be looking at how /run/gdm3/custom.conf is created, whether the logic in /lib/udev/rules.d/61-gdm.rules is correct, and whether using X.Org (in Debian 12) instead of Wayland (in Debian 11) is really justified on the particular machine (https://gitlab.gnome.org/GNOME/gdm/-/merge_requests/171#note_1403697 doesn't apply in my use case because the onboard graphics chip is usually not connected to a monitor in my setup, except if the monitor connected to the PCIe NVIDIA card happens to fail, which has not yet happened). If this issue involves the kernel at all, then probably the nouveau driver. The details of this issue are beyond my level of expertise, so I'm unsure how much I can really do myself.
Gratefully, Alma