Ahhh, i had that with my ps5 and a couple of games were terrible in hiqh quality graphics mode, shutting down the ps5, and then through hdmi, would turn off the tv.
Both games weren’t particularly intensive, the one i remember last was divinity original sin 2, but i think both games ran on unity.
Performance mode mostly fixed it, but blowing out several years of dust from the vents properly sorted it out.