+1
Actually not sure if this is the same exact issue, butI have an album, WILHELM FURTWANGLER - WAGNER DER RING DES NIBELUNGEN. It is 13 discs with about 320 tracks total (22-24 each). It is painfully slow to come up in the UX; approximately 15+ seconds on a late 2016 MacBook client and an i7 NUC server. Guessing you’ve got an o(n^2) operation (or worse) going on somewhere.