This morning i saw the 601 dev update,
So i just did the update not knowing what to expect. After the phone fairphone 4 had restartet and I opened my music-player and the gallery app as usual to preload its content for the day (as i had to do multiple times a day).
To my astonishment the gallery app opened straight away and displayed immediately all the pictures stored (this could take up to an hour before) same goes for my music library and when ever a new file would be added the rescan of content would start a new...
I dont know what fixed the issue or if it fixed itself.
But it didnt happen with the previous dev 600 update
So thank you all.