The Last Guardian - HDR Optimized Settings
Added 2022-03-14 15:28:59 +0000 UTC
The game is NOT using/applying Playstation HDR Calibration app settings.
Measured Peak HDR Brightness of the game will reach 10.000, but rarely. Common HDR Brightness is ranging between 700-800 nits, but there is no way to control/modify it.
For this reason it is suggested to use Dynamic Tone Mapping in order to offset potential highlights clipping and lost detail in bright areas.

The game has a regular "Brightness" slider which is recommended to leave at Default/Middle as it already corresponds to a balanced/correct exposure and gamma.