usually this happens when I fall asleep on top of the remote... what I assume happens is that the remote touch surface gets pressed, constantly for a few hours under my body weight, & that causes issues in the morning when I go to use it. re-pairing always fixed it in the past.
so I tried “unpairing/re-pairing” using menu + volume up for a few seconds (per Apple support page). but that did not work this time. hmmm...
found this advice above, and immediately after using Siri to open an app, the remote started working normally again. also fwiw, the battery level in settings said it was 98% before I used Siri, but after it now says 100%. super weird. yet super grateful for solution. Thanks!