Pairing iPhone 6 with iPad Pro via Bluetooth

Hi,


I can use MultipeerConnectivity via WiFi to have 2 iOS devices communicate with each other. I would like to test this same app with Bluetooth alone. When I try to pair an iPhone 6 with iOS 12 with an iPad Pro with iOS 13, it does not detect each other.


Yet the iPhone 6 can pair with my iWatch and both iPhone and iPad can recognize the Beats headset.


How do I get the iPhone to detect the iPad and vice versa via Bluetooth?


Thanks.