Interesting. 4K is mostly a lie.

https://www.youtube.com/watch?v=yN0H_WfWOp4

The Biggest Mistake in the History of Hollywood

YouTube
@Gargron He is only talking about movies, but especially Netflix has some strong requirements for its production contractors about specific 4K cameras and CGI + editing in 4K in series. They want grounded reasons to upsell you to their 4K plan, so 4K series on Netflix and Prime are usually true 4K productions with a complete 4K DI pipeline.
Newer cinema movies of the past, say 6 years, also do often have whole 4K production pipelines (just don’t expect it from Disney).
@frumble
Even if the actual movie is all 4k, the stream has a limited bandwidth of ~ 25 MBit/s -> lossy compression.
@innerand Of course, but it’s H.265 HDR on streaming services vs. H.264 SDR on FHD Blu-ray, that makes comparisons crude (compression with HDR is also more efficient than SDR). 25 MBit/s 4K can look excellent with the right encoder, it’s just not the actual standard bitrate of those services.
80 MBit/s UHD-BDs do look better, of course.