Initiate connection with Gadgetbridge from the Bangle?

Gadgetbridge could be made a peripheral I think, but I don't think it's a good idea. With other devices being able to initiate a connection there's a worry that maybe anyone could then connect to your Phone and access your messages, phone, etc.

With Gadgetbridge as a 'central', it's always up to the phone to initiate the connection.

Why do you want this though? Are you having problems getting the bangle connected?

If so there's a (default off) automatic reconnect option in Gadgetbridge, and when your phone's power save is disabled for Gadgetbridge it's usually pretty good at keeping connected