Some people still think HDR is only available in 4k (because that’s how most movies are distributed). But you can absolutely fit an H.265 HDR 10-bit 1080p (or 4k) movie on a data DVD±R, or H.266 HDR 720p on a CD-R. It’s usually not worth the effort, though.

And you can only appreciate the resolution if the screen takes up enough of your visual field, and HDR only in a glare-free dark environment. My small LCD TV offers neither so there is no reason to download movies above 720p (even DVD over RGB looks sharp on it).