although it talks about xiomi box, first read @ New player wont play any 4k HDR files and see if any of that is applicable
while streaming a problem video/buffering
- post screenshot of plex web > dashboard (I know you already posted one above)
- attach logs, preferably a clean stop/start > play problem video for a couple minutes > stop video > download logs > upload logs to post here
- you may also want to provide client logs (see @ https://support.plex.tv/articles/201573117-android-android-tv-fire-tv-logs/)
