Upon testing both Xbox SX and the PS5 I have found the Xbox SX to work better for the plex app including live tv! That was my purchase deciding factor so I hope it helps someone.
Xbox series x problems
Still buffers alot when starting live tv
Fails to start live TV sometimes
Transcodes mpeg2
Ps5 problems
Crashes alot
Mpeg2 Transcodes
H265 causes peoples skin tone to be bright red