Guys, I believe it is the same thing as everything else - it's flickering of some sort. Remote streaming helps alleviate the problem by video compression.
I never had PS5, but xbox SX was terrible, it was way worse than even my current PC that I don't like at all. Tried it on several TVs and one monitor. Some TV processing was able to hide it to some extent, but not entirely. Streaming to a PC was better, almost usable. But I returned it anyway.
As I am very sensitive to any sort of flicker and am usually able to really "see" the instability I can tell you that it was there, I am sure of it (again, on xbox, not PS5, but I am convinced the problem there is just the same).
I think that some very good TVs (high end OLEDs?) and their processing could hide the problem entirely, but it's really hit and miss.