Yeah, there are really loads of options.
Is CarPlay controlling the volume, like in your case
Is the CarPlay device paired to the headset additionally to the phone
Is the phone directly paired to the headset
Or like with my chigee, CarPlay is only for visuals and phone controls volume.
The system settings helped in my case.
And also fixed the sound issues I had with Garmin Connect and my Forerunner watch,
I even think that was the culprit changing my default voices to something absurd and quiet.