(solved) Local folders gone

I’m marking this case (see below) as solved because I found the reason for this in the thread Android app doesn’t work correctly.
Though I don’t like what this leads to, I guess there is no way around it.
Now I only have to find out, where I can get the latest old version of the app that still uses the android file system to store files.

Actual behaviour

  • Tell us what happens
    Local folders of ownCloud Files have been deleted.

Expected behaviour

  • Tell us what should happen
    I should be able to select the local folder, where the offline copy of my files are stored.

Steps to reproduce

I recently updated my ownCloud Android client (now Version 2.20). Don’t know, which version I had before.
Now I found, that all the folders where the local ownCloud files had been stored have been deleted.
I can only access them via the ownCloud App, which is extremely uncomfortable.
After some searching I found, that the new Android App version uses “scoped storage”.
This “feature” seems to make direct access to my files impossible.
Also I would like the app to make regular sync checks in the background. I have found no way to set any synchronization intervals for background sync (maybe the way, CalDAV-Sync does for the ownCloud Calendar).
Is there any way to get the ownCloud App working similar to the Windows Client, which just syncs my files without trying to build a complete file manager/user interface?
Or is there an alternative Android App than can sync ownCloud files as background task?

Environment data

Android version: 11

Device model: SM-T970

Stock or customized system:

ownCloud app version: 2.20

ownCloud server version: 10.0.2