Storage Location cannot be selected in Graphene OS

App version: 2.2.1F-Droid
Android version: 11.x (Graphene OS)
Device model:
Google Pixel 4a

I am trying out Antennapod.
I would like to change the storage location to the standard podcast folder the OS has created.
But the option to choose a storage location for downloaded podcasts is unresponsive (as in Settings → Storage-> Choose Data folder).
What am I doing wrong?
Help would be appreciated!

Same thing here!
It would be nice to have a solution, because the automatic download is then impossible.
Access to Data folder is forbiden, probably by GrapheneOS.