chronic bluetooth headset disconnect & reconnect

My Jabra Steel bluetooth headset suddenly started to disconnect, and instantly reconnect from my iPhone 8 for no reason. The phone is less than a month old an has worked flawlessly for most of that time. The phone is on my belt ,and the headset is in my ear 99% of the time. It also happens intermittently when opening the phone from a locked screen or, opening and switching apps. I contacted Jabra and they had me reset the headset and forget the device but, I fear it is something with the phone, not the headset because of the latter situation. I've gone through the setting that I can find that might be related.

Ideas? settings?