Hi Ben, if using SongKong with Roon profile it does add an album tag but only for boxsets to try an overcome difficulties users have with Roon and its boxset support, but they are only added for boxsets, and this customer only has 20,000 tracks of which I expect most are not boxsets.
It seems very unlikely this is the issue, especially since this was suggested as a solution to another users problem but removing them made no difference - Large Collection (280,000 Tracks) Slow search - #306 by Ronald_Lyster
But you can remove them by running MetaGrater task on your lib, and adding the Roon Album Tag field to the Delete all metadata from these fields option
And I don’t understand where this figure of 73,000 tags comes from, or when you say tags do you mean all metadata fields such as artist, performer ecetera ?