I just created a tutorial video on how I got Bluetooth MIDI to work with Cantabile (you need to do a little bit of virtual wiring):
Although there actually is a Bluetooth-MIDI API for Windows 10…
…it’s not yet widespread in the Windows eco system’s music software, because every developer has to implement it explicitely in his software.
If you feel like this should be a built-in feature of Cantabile, you could upvote in Trello:
https://trello.com/c/OeOorRce