I use beets.io for all of my tagging, conversion and overall music sorting, with it having MusicBrainz, Discogs, or Beatport metadata support I always tag my files before Roon even gets to see them.
I do see that there are times when Roon see’s them as ‘Unidentified’ but I know that beets has fully tagged them, so I don’t mind.
I am not entirely clear on the consequencies of that, but for me the pre-processing works.
Edit: Typo.