I am experiencing a similar issue with Bluetooth and audio signal transmission. Using iOS 14 Public Beta 2 (18A5332f) on my iPhone 11. Haven't actually tried with my Airpods (1st gen) or Beats Studio 3 wireless headphones, but I noticed today that my phone wouldn't correctly send audio to my Bluetooth stereo in my car. My phone would still show as "connected" to my car's bluetooth but wouldn't send the audio signal out to the car stereo. Did not experience this with earlier Public Beta. I have tried toggling iPhone's bluetooth off and off, as well as unpairing ("forgetting this device") and re-pairing with my car's bluetooth device, but I get the same behavior.