I had lots of problems with the FlatPak version 1.0.23.

I'm still running Linux Mint 21.1 Vera (base: Ubuntu 22.04 jammy).
When I realized how out of date the package was, I installed from repository.
https://linuxcapable.com/how-to-install-strawberry-on-ubuntu-linux/

Then I had to move my library and all data to the newer location.

In the old FlatPak version, the following were in ~/.var/app/org.strawberrymusicplayer.strawberry
albumcovers/
collectionalbumcovers/
strawberry.db
strawberry.db.bak

I uninstalled the FlatPak version of strawberry then installed newer version (1.1.3), from repository, as above.
Then I moved those db files and folders to ~/.local/share/strawberry/strawberry/

And everything works for me.

Good luck!

I have had luck using touch to update the modified date of the artist folder. When I invoke "Update changed collection folders", it then seems to scan all albums and song within.