I can't find the solution post that you seem to be referring to here. The closest I've found is a link to Reddit where someone said "Turn off Sync Library and a

I can't find the solution post that you seem to be referring to here. The closest I've found is a link to Reddit where someone said "Turn off Sync Library and all that data will come back". But the original user responded saying that while the majority of songs came back, a few hundred were gone for good, and that Apple Support told them "sometimes that happens". Is there a different, better solution that I haven't spotted yet? Or, what was the misunderstanding?