Apple is the undisputed champion of bitrate. Their streams are less compressed than Netflix. Tiny World (narrated by Paul Rudd) and Prehistoric Planet are shot specifically to exploit HDR contrast. Apple also allows you to download 4K HDR files directly to your iPad or Mac.
Have you watched a great 4K HDR nature doc on a portable device? Share your setup in the comments below. 4k hdr nature documentaries portable
Here is curated content for optimized for portable devices (phones, tablets, and laptops). Apple is the undisputed champion of bitrate