Iphone12 with ios16.4 randomly switching to Bluetooth headset device during VoIP calls

Iphone12 with wired headset (apple lightning) in Teams voip call. But suddenly, iphone switches to bluetooth headset in the call. In settings-> bluetooth, I do not see any bluetooth headset being connected. In Teams call, I am unable to switch from bluetooth headset to wired headset. I have to disconnect the teams call, and reboot the phone in order to get Teams call working properly.

Associated with this issue, Iphone12 randomly changing my ringer volume to max 100 times a day. I have to keep pressing the volume button to keep bringing the ringer volume down.

Rebooting the iphone, unpairing and re-pairing my bluetooth headsets, and other ideas in the community threads do not work. This problem has been there for a few months and cannot find any solution.

PLEASE HELP !! HOW CAN THIS PROBLEM BE FIXED ?