Hi there,
Good old Asspreso , rug-pull or bait and switch 
… So the Solution mark, Should be on the post bottom. I would concur on the use of NimBLE LIB for some of the more advanced BLE capabilities and robustness, I use it in the Multiconnect (3) to (1) with 6 concurrent Notifications. 2 for each Peripheral.
Time permitting tonight I will post it up. Demonstrating the connectivity and the Caveats when using it. 
HTH
GL 
PJ 