Another "Aha!" moment:

I have two 4k monitors and a 1080p monitor connected to my Lenovo laptop, plus a camlink pro 4k. I had been having an issue where occasionally, the computer would lose its mind - hanging, stuttering audio, and apps crashing, etc. I assumed I was pushing the USB bus a bit too hard - after disconnecting the camlink, things would settle down after a few minutes. The problems were 100% repeatable, on two different laptops.

Turns out the problem is heat. I pointed a desktop fan on the laptop and have had zero problems since. The laptops are overall more responsive, too.