my library has around 3000 artists / 5000 albums / 8500 composers / 75000 tracks
I think I have found partially a root cause of this issue . It may be related to the Wifi 2.4 Ghz / 5 Ghz.
Before, I had a single SSID for both frequencies, letting the ISP box choosing the best one.
Now I have separated the SSID : one for 2.4 Ghz and the second one for the 5 Ghz band. Ipad is connected to the 5 ghz band, only. throughput is around 70 Mb/s, stable.
and now browsing is really fast : even when scrolling fast in the middle of the artist page, pictures appears in around 2-3 seconds.
The remaining action that still takes a lot of times is within the artist page : you may choose to view album artists or interprets or ensemble or composer.
here are the differents actions I have timed
1- switching from album artist to interpret : around 20 seconds . going back to album artist is almost instantaneous.
2- switching from album artist to ensembles : around 2 seconds. going back to album artist is almost instantaneous.
3- switching from album artist to composers : around 1 min 50 sec. going back to album artist is almost instantaneous.
during each of these actions, one core of the server is running full throttle. and it is reproductible… Task duration seems to be linear with the number of the filtered items.
The same actions performed on the PC interface are nearly instantaneous , without any long CPU activity.
Hope it helps to investigate this issue !