I bet that old TV has some form of early adaptive sync on it. The Driver with their "gsync comparability" option probably tells the firmware on the card (nvidia has their own little risc processor running firmware with its own memory) hey this montior supports adaptive sync set 45-75hz or whatever the case is. The issue is the TV and most early freesync monitors are a little wonky on their min hz (even their high hz for that matter). I suspect (could be way off) that the windows driver is setting the on board GPU firmware monitor out settings to the EXACT expected HZ like 45.0 to 75.0. Anyone that has had one of those early freesync jobs knows you want to set 1FPS over the min and 1FPS under the max on a frame limiter to avoid oddness. When I used Radeon Chill on a 45-75hz freesync monitor I would always set 46-74. If I set 45-75 I would notice odd studders/tears occasionally.I thought about flashing another firmware to the RTX 3060, but when I looked up what versions were available on TechPowerUp, I realized the firmware on the card was newer. Since the problem goes away using his monitor, I figured I'd just ignore the problem.
That is my though on what is going on anyway. Seems to be some sort of issue with monitors that don't quite meet the spec reported to the software. Their software should probably build in 1-2hz buffer for non Gsyn chipped monitors. Might be all they need to do.