Gran Turismo 7 - HDR Optimized Settings (Patreon)

The game DOES USE/APPLY Playstation HDR Calibration app settings.

The game has a good HDR implementation and it's one of the few games actually leveraging system-wide HDR settings. 

It also offers additional control over Exposure and Saturation:

You can leave "Exposure Correction" slider to: 0.0 EV (Default) and "Adjust Saturation" slider to: 100 (Default) as this corresponds to a balanced/correct exposure and gamma.