OK, I guess I'm a glutton for punishment. I disconnected my small lcd panel, but decided to give Sensor Panel one more try. I got it all set up the way I wanted, keeping an eye on the memory usage the whole time. While I was working on the panel setup, it started out around 80mb, and eventually climbed to around 110mb. Then I setup the panel on my secondary monitor, and set to gaming.
One hour of GTA V, ultra settings, 120fps frame limit, no freezing/lockup. Followed that with an hour of Starfield, also all ultra, no frame cap, still no problems. Also, the memory usage while gaming dropped to around 10-11mb. I'll keep the Sensor Panel up for the indefinite future, to see if it's going to try to freeze on me at any point. So far, the only common factor in all of my lockup situations is the existence of a small lcd monitor meant to operate as my sensor panel, which makes little sense. It's something I can live with if it continues to work on my secondary 24" monitor, because I don't need it while gaming.