How to remove tag spam and set language in several MKV files at once

You may want to set the language of your audio while you are modifying the files. This will help with displaying subtitles when needed(if set correctly).
track:a1 --set flag-default=1 --set flag-forced=0 --set language=eng
This assumes english(eng).

Though I strongly suggest you use caution with the command --delete name on tracks cause you could be removing detailed descriptions of the tracks. Things like a “commentary track” or “Subtitles - SDH”, or similar.
More on what I am trying to say.

While Plex doesn’t support this(yet). I hope someday it will.