Thank you for posting this good, detailed, information on your test.
Thank you especially for showing the use of -fflags nobuffer. that may resolve some of the problems.
I’m going to test this in Windows 10 after I reinstall my OS.
I just tested the parameters you posted on Ubuntu 20.04 and it works great.
$ ffplay -version
ffplay version 4.2.4-1ubuntu0.1 Copyright (c) 2003-2020 the FFmpeg developers
built with gcc 9 (Ubuntu 9.3.0-10ubuntu2)
I wonder if there is a way to disable buffering on Pot Player on Windows 10? It has nice 360 navigation of the stream.
Just to share info, I’m getting some frame degradation at 4K on my network with ffplay. It still works, but the 2K stream is clearer.