Add possibility to set up folder pairs in the Android App

I tried to setup the App in a way that it mimics FolderSyncs behaviour:

1) Define source and destination folder pairs
2) Setup what's going to happen and when (one way, two way, conflict resolution)

While 2) is optional, I wasn't even able to get 1) working.

For example lets say I'd like to do a two way sync /storage/emulated/0/DCIM to /My_Phone_1/DCIM on Nextcloud I simply can't do that.

I can only auto upload select /storage/emulated/0/DCIM/Camera (not able to select the root Folder DCIM) and then all my files get uploaded.
Ok but never downloaded, I can only download them to Ownclouds own data directory. Which makes no sense if I for instance have a new phone and just want to keep my DCIM folder in sync. Right there where it is on my phone, not in Nextclouds Data directory.

FolderSync can perfectly do what's neede but it's a non free closed source app so I'd like to get rid of it.