I use the 65" TV in the living room for playing video games (my desktop is connected to it) and usually, there isn't a problem at all (either 1080p SDR, 1080p HDR, or 4K HDR).
It seems like when I play something in 4K SDR mode, though, the display appears to sometimes black out along with the audio cutting out, before recovering. While it's displaying, I can also see random red noise on dark or black areas of the display. This doesn't happen in any other mode. For something like Skyrim SE, this isn't really much of a problem due to the game's pacing, but it's very jarring when playing Forza Horizon 3.
On my back-of-napkin maths, 4K YCrCb 4:2:2 10-bit, 1080p RGB 12-bit both push less bandwidth than 4K RGB 8-bit. Could 4K in SDR mode be a bit too much for the cable I'm using (since I actually just picked a random High-Speed cable I already have which, admittedly, has been laying around for a very long time)