Map folder (look around, I don't have it in English): Settings > Osmand settings > Data folder
You should see the exact folder written under the general name (Intern/Extern/...). In your case, it is problably Apps internal memory or something like this.
Check that you see the same folder here as you have found in memory ( Device storage/Android/data/net.osmand )
I had similar problem, rewriting the part "/sdcard/" to "/storage/emulated/0" helped in my case. No idea why it didn't "take" the aliased folder, other apps didn't need it. In your case, I would suspect the "device storage" part.
Yes, the obf files are maps. You could move the complete contents of the Device storage/Android/data/net.osmand folder somewhere else, uninstall Osmand and reinstall it. Start it, check where it wants to install the data. Move the "old" contents to this new folder.
Don't uninstall Osmand without moving or renaming the folder first, this one would be almost certainly deleted on uninstall.
Majka