The easiest fix: go to settings/customise my library/ and deselect everything except songs and then use the app
I have ASUS Max pro m2(Android 9), after following you step, still no magic happened
My music library is in ext sdcard, foobar2000 can pickup every new album I add
But Android foobar2000's UI is such a disaster ?
Jetaudio can't find them too
I've tried :
1. Install sony album and use its "find and fix problem"
2. Clean cache and data from Android setting and recovery mode
3. Check if there is .nomedia in the folder
4. The method you provided
PS when I applied Asus ota update, those albums will show up magically, but add more albums to it ,sony and google music just can't pick them up