What is your current media player of choice?
I have tried lots of different players and all seem to cause issues to varying degrees. The latest VLC/MPC-HC/Pot Player/Kodi etc cause strain. The only player that seems most comfortable for me is MPC-HC (2010 build with XP renderer selected) or Windows Media Player (however you need to convert to MP4/codec pack for use with some formats).
I was thinking of using an all in one player like PowerDVD, or something that supports H264/MPEG-2/XVID and disc playback. I have tried PowerDVD 2018/2019 and even on my good setup it gave eye strain. I suspect modern rendering/decoders in these players are to blame.
Another unusual player I can recommend is Edge browser. It has built in H264 support, you do need to convert to MP4 for playback to work and I don't think it supports subtitles, but I found it to be reasonably comfortable. Strangely, when comparing two windows side-by-side, one of a YouTube video and another of the same video downloaded as MP4, the whites seem slightly brighter/yellower on the local file compared to YouTube itself. There must be something happening behind the scenes on local playback which doesn't happen during streaming.