I'm having the same problems. It's horrible. I relied on audio streaming for taking work calls. Now, after installing iOS 13, whenever I get a call there's a 50/50 chance it won't work. And it doesn't even play to the speaker on the phone. The phone actually says it's streaming to my hearing aids, but I don't get any sound. Or I'll start a call and it'll randomly connect and disconnect. None of this happened with earlier versions of iOS. Absolutely horrible - it's like Apple has no quality control anymore.