fwiw I have deleted and re-built my library several times (I only use TIDAL, no files).
But I suppose you could say I have a “mental library” – certain artists / albums / tracks that I know and love, and can use as a starting point for searching from TIDAL.
My biggest challenge right now is dealing with “candidates” for inclusion to my library. TIDAL has a bunch of new releases and recommendations that I’m sort of tangentially interested in, without knowing much (or sometimes anything) about them.
How do I handle those? Add them to my library and tag them? Add them to my library and hide them? Add candidates to library, favorite the albums I know & like, and tag my “super favorites” ? I’m continuing to work this out (and maybe it’s a question for How do you Roon?)