audio quality issue iPhone 12 pro

When I had my iPhone 6S, I would use the headphone output to connect to my church sound system to play recorded music. Sound was perfect and I could vary the volume with the phone. With my new iPhone 12 pro, using the Apple lightning to headphone adapter I get distortion and muddy tones regardless of volume level.

When connecting, my iPhone 12 asks whether I'm connecting to a headphone or to something else and my choice seems to make no difference. I am mystified, obviously the lightning to headphone adapter is not the equivalent of the actual headphone jack of previous iPhones (and iPads). I wonder if the Apple headphone safety circuitry is causing or whether the direct connection using the adapter is just not possible. Any helpful solution thoughts please? Do I need an additional adapter or interface?

Interestingly, connecting to my Bose and Sony stereos using their built-in iPhone connection removes the volume adjustment from the phone and plays perfectly thru the stereos.

Bluetooth is not a present available option on the church system and the one situation I experimented on another system produced distortion. The church system input is XLRM connector, balanced low impedance across pins 2 and 3, and worked perfectly with the old actual iPhone headphone output.

thank you.