@TheOnlyYetti
I have the C3 and I did select the "use for non-supported games" VRR option and my tv does show that I am getting 119-120 fps in game (while viewing the TV game settings menu).
However, I do not notice a (gameplay) difference in online H2H games, as compared to not selecting that option, with all other things being equal. I believe the game was designed for only 60fps at 4k max for the PS5/Xbox X/S, so I am not sure what the true benefit of selecting this option is.
The only thing I can say for sure, is that turning on the option, did not have a negative impact on gameplay. The PS5, used with a HDMI 2.1 display, is excellent with or without that VRR option being selected.