Device: OnePlus 3 (same issue also experienced on Pixel 3A)
Operating System: Oxygen OS (and Android 10)
I have been experiencing a consistent lag (of approx 5 seconds) when selecting an Artist or Album (but not playlists) from 'My Library' on my OnePlus 3. Strangely, there is no lag when selecting Artists/Albums from 'Home'. I thought the lag was due to the phone slowing down (it's about 4 years old), however I have recently upgraded to a Pixel 3a and I am experiencing the exact same issue.
I logged in with a family member's account on the same device and the lag disappeared so I suspect the issue is with the account.
Let me know if any more information would be useful! Any help welcome.