HDR is High Dynamic Range. Makes your monitor more colorful and realistic, closer to what you see in real life. Bright scenes are brighter, colors are more vibrant and accurate (for example, you can actually see teal properly with an HDR monitor, which normal monitors can't display accurately). Requires a compatible monitor. You would know if you had one cause most people don't spend extra money on a display unless they know/care about this feature.

RTX Video Super Resolution uses AI to sharpen and upscale lower resolution video. It's useful for watching 1080p videos on a 4K monitor. Or for watching 720p videos at 1080-quality because your internet sucks and can't handle 1080p. Requires an Nvidia RTX graphics card (again, you would know if you had one cause they're expensive and meant for PC gamers).

Basically I'm complaining about features that only enthusiasts care about, but Chrome supports them so why not Firefox too?