I have confirmed today that this is still not working in that version, or the current beta. When I try to enable BT in the current beta I get "Permissions were refused and may need to be granted manually". On a fresh install, I got prompted for Nearby Devices and it currently is enabled.
Since my initial message, I had to factory reset the tablet (due to an unrelated problem) so this is a completely fresh install of OpenSong that is still not working; as is the beta. I have tested the MIDI in Songbook Pro with the exact same hardware and it is working fine.