Thanks for your response. I just started following your instructions, but then suddenly realized Roon is actually as responsive as before and pretty fast! Not sure I have an explanation for this, but I did one thing yesterday. I attempted to reduce my library size (honestly want to do this), so I deleted like 7000 albums. Again it seems like those got added back in the course of several hours (I had experienced this before: Roon Slow; Deleted Qobuz Albums, but they get Re-Added), and now it’s back to 21k albums. Could it be that this sort of re-indexed the database or something and it got fast again as a result?
given that its performance is acceptable at the moment, do you recommend I still follow through your instructions?