Lost music library, how can I recover it from offline files?

Issue description:

As per title, I lost my music library on my server (due to severe mistakes on my part, I managed to lose the volume and its backup, yeah…). I am very technical, but I’m not very knowledgeable about Android, unfortunately.

Fortunately, I do have the entire library (not a huge one, fortunately) downloaded as offline files.
My phone’s not rooted, so I believe there is no way to recover the files through adb or similar. The in-app backup does not appear to include, even when selecting all the switches, the offline songs.

Is there a way of downloading the library from the app that I’m missing? Does anyone got an idea if there’s other options?

If there’s no other option available, would it be possible (though I know this is asking for quite a bit of help) to have a debuggable=true apk? That may allow me to use run-as in adb.

Logs:

Upload description: kalex

Additional information:

 

 

Reproduction steps:

 

 

Media provider:

Subsonic

Screenshots:

     

You can use the export to download folder to export to a readable folder.

The backup have json content of your likes, last played and everything that you also can probably script to recover.