So I just bought a OnePlus 12 recently, I was used to controlling volume using the onehand operations goodlock module in my Samsung galaxy S23. I basically never had to press the volume buttons to control the volume unless absolutely necessary.

Possible ways I've thought of (it would be really great if at all possible) -

1. Using the curved edges in phone screen for volume control.

2. Using the gestures to control volume when the screen is off.

3. Setting Diagonal swiping gestures to do different functions, controlling volume in this case.