Personally I wouldn’t be looking at Netflix as a good source of 4k. While it can spit out the resolution, the content is likely variable bitrate encoded and the stream is variable bitrate depending on your broadband.
There ain’t nothing wrong with variable bitrate, especially given the level of sophistication of encoding.
Also Netflix use an extemerely clever system of encoding, far beyond discussion here.
netflix teccy
Basically they’re ahead of the game of most other streaming platforms.
There are better ways to serve 4K but our almost lossless Red Raw needs 80MB/S to see in total glory so there’s bound to be trade offs.