I have a C3 OLED and everything also looks better with HDR off.

Games are just truly awful in making scenes completely in viewable, even when the HDR areas, the blacks and whites, have interactive elements in them you need to see and know about.

I have a C4 OLED and I thought what you said was also true for me until I figured out what settings I needed to change on my TV to match my console (Nintendo Switch 2). Had to turn on HGiG, manually adjust the peak brightness level on the console itself, and suddenly things looked great.

Not that many games on the console that take advantage of it, mind you. More testing needed.