Primitive ftpd - sdcard access?

[timg11]

I installed Primitive ftpd 6.11 on a tablet with Android 11. I want to back up the Android files to another server using a sync script.
I select SAF storage. It opens the Android file picker. Whether I select the root of the internal filesystem, or the root of sdcard, the picker says “Can’t use this folder”

Presumably I could create a new folder, but that is not helpful.
The whole point is to back up the file system, not one specific folder.
Is there a workaround, or is the SAF unusable for this purpose?

I read that Android offers Manage All Files Access for this purpose, but it appears to need to be part of the app.

[Licaon_Kter]

@timg11

I select SAF storage.

All the other options don’t work?

[timg11]

Correct - other options do not provide access to External SD-Card. Is there a workaround?

[pazos]

It is a framework restriction for apps that target android11+. See Storage updates in Android 11  |  Android Developers

Use an older version targeted against android 10 or below.