To only set genre and year you can use this list: Only set a single tag in Picard (complete $unset tag list)
It’s already noted in that thread, but worth repeating:
- Backup your files first, tag changes or tag deletion cannot be undone, and Picard allows you to make a lot of changes very quickly
- If you’re going to the work of matching your files in Picard, you really should keep the MBID tags, which will save you having to do the work again if you ever want to update genre etc
Getting the year from MusicBrainz should be okay, you just have to decide if you want to get the year of specific editions (e.g. the year of the exact CD you ripped), or the year of the first release of that album in general. You can tweak what data you want and where you want it via Picard scripts and these tags: date, originaldate, originalyear
Genre can be a bit all over the place still.
If you spot information and genres that is wrong or missing it would be much appreciated by others if you fixed it or add it 