It's looking like my occasional freezes in Linux Mint 22.0/22.1 were much more likely to be a memory matter rather than one centered around Nvidia drivers or Linux Mint itself.
Sadly the first time around when I used Memtest86+ to test my memory, I didn't hang around for all ten of the total tests it does. Had I let the program run its course, it would have shown me that I had a memory failure on test #6.
At that point, the real question was whether or not I needed to replace one or both memory sticks. So the first and most logical thing was to remove both sticks and reseat them in their A2 and B2 banks (slots).
Rebooting the system, I then defaulted to using my Mint ISO flash drive, which conveniently has Memtest86+ in the boot menu. In running the program a second time after reseating my memory sticks, voila! - All ten tests passed. For the first time with months of troubleshooting, I finally had something conclusive about what was happening all this time. It does seem to run a bit faster, and without problems whether booting or shutting down, and no freezes since then. Stay tuned....
Yet it seemed too simple! But then had I researched the issue in much greater detail, I would have been able to understand how this simple solution was likely the most plausible one:
Reboot Your System: Why Reseating RAM is Crucial for Optimal Performance - SoftHandTech
So now in as much as I routinely clean the guts of my computer (mostly to get rid of any dust), I will also be taking out my memory sticks and gently re-inserting them, making sure they are clean and sitting solidly inside both channels A2 and B2 to optimize my dual-layer memory.
My biggest uptake: I realize now that even buying top grade memory is no guarantee it may fail at some point, without a need to replace it. I just had no idea how fundamental an issue this really is.