HDR video/images in the macOS/iOS browser have to be one of the most confusing UX in recent memory.
Why are people able to craft an image/video that bypasses my screen brightness and color shift settings?
If I wanted to see the media in full fidelity, I wouldn't have my screen dimmed with nightshift turned on in my dark bedroom.
It's not OP's fault. My mind is just blown every time I see this behavior.