Greetings,
The first thing I would do is a full camera reset, main and custom settings. If you have a large number of customized settings, you can make a backup to an SD card before the resets.
If this doesn't help, this could be a build up of skin oils, moisture, dirt, grit or other foreign debris. It could also be a hardware issue / button failure.
Grab a few old business cards and be very gentle. See if you can work the corners gently around the crevices of the button and dial. You can follow with a rocket blower.
If none of this helps, you'll need to contact Canon support to have the camera inspected.
~Rick
Bay Area - CA
~R5 C (1.0.6.1) ~RF Trinity, ~RF 100 Macro, ~RF 100~400, ~RF 100~500, +RF 1.4x TC, +Canon Control Ring, BG-R10, 430EX III-RT ~DxO PhotoLab Elite ~DaVinci Resolve ~Windows11 Pro ~ImageClass MF644Cdw/MF656Cdw ~Pixel 8
~CarePaks Are Worth It
