Comment by AlanYx

That option only works with Apple's XDR enabled displays (internal and external). For non-Apple external displays with HDR10, there's a separate "High Dynamic Range" toggle in the display settings in the display. On some Intel macs, if you open Display preferences while holding down the Option key, another option appears to disable simulated HDR. I'm not sure how to disable simulated HDR on the internal display of current Macbook Airs.