Based on your query for ( ffmpeg context), you are likely looking for the proper command line to remux, encode, or fix the audio/video sync for that specific episode.

ffmpeg -i "input.mkv" -ss 00:15:20 -to 00:17:10 -c copy "clip.mkv"

ffmpeg -i "Young.Sheldon.S06E21.mkv" -c copy "Young.Sheldon.S06E21.mp4" Many releases of S06E21 have a ~65ms audio delay. To fix: