Ya, it's sad that there is no one best way to watch that show.
US Streaming = No 5.1, no HDR, lower bitrate
International = 5.1, HDR, lower bitrate
Blu-ray = 5.1, high bitrate, no HDR
I was really shocked when I learned there wasn't a 4K version of it at all when it first started airing.
A 4K Blu is likely down the line because the international Netflix trailer is in 4K and the first two episodes were originally streamed in 4K internationally.
I've heard that the show was filmed in 4K, but the effects were rendered in 2K, tho there are plenty of films with a 2K DI. That shouldn't prohibit a 4K Blu.