'Caching and offline playback': not working

[slynobody]

issue: advertised funcionality: 'Caching and offline playback' (main page) not working

Context: app used offline (WiFi/Mobile data disabled) with downloaded playlists.
Reproduce Issue: go offline, switch to 'library' / 'downloaded playlists', choose album

Results: black screen ('indicator: hourglass / waiting / fetching')
= no direct album-art-cache display (supposedly hanging while trying to fetch data online !while being offline!)

Symptom: Music playback works, but navigating to albums results in black screens continuing to load indefinitely.
ui: Album covers seemingly missing in-app , though they appear correctly in the One UI 6.0 notification panel.
workaround: inside 'library' / 'downloaded playlists' press album > black screen > navigate back (iterate): album & art show up randomly (sometimes 3-7x back, sometimes 5-15 times), data is there but not handled right in this context.
if you dont want to fix this, please at least give hints on compiling source (link on main page).

also see this 2 year old reddit-issue usablity of caches inside downloaded playlists (reddit, not fixed)
also see: #1604 #1292 #1753 #1750 #1576

would be interested what is planned on this.

[slynobody]

workaround: usage of internal android-vpn (blocking ads etc.) -- and there: disabling simpmusics net-access completely (resulting in simpmusic recognizing this as 'offline-mode', whereas simply turning of wifi: not enough)