Please turn off verbose logging (Settings → Server_Name → General). It is not needed and can cause the log files to wrap too quickly.
At least part of the problem is subtitle burning:
Dec 19, 2021 10:25:47.548 [0x7f03c1b1cb38] DEBUG - [Transcode] MDE: E1 - Assassination Time: selected subtitle cannot be converted to a compatible format, burning into video stream
Edit: Matching 12:40 playback.
Dec 19, 2021 12:40:10.376 [0x7f03c0998b38] DEBUG - [Transcode] MDE: E1 - Assassination Time: avoiding video remux due to burned subtitle stream
This post provides details on the process. Ignore the part about the video driver. It is not relevant here.
Unfortunately, ASS subtitles are a problem for many Plex clients, including Android/Android TV. Enabling them results in a video transcode. You can try changing Burn Subtitles from Automatic to Image Formats Only in the Plex client app, but you will probably lose formatting information in the process (positioning, colors, etc).
