Nothing to do with decibels but the thermostat on the water heater might be set too high. If one lowers the overall temperature the ratio of cold to hot will balance.

You are bounded by a minimum floor for the hot water. Below a certain point you can get legionnaires.

To me it seems like one of two things: external pressure between hot and cold is mismatched so a small change to one side overwhelms the weaker flow.

Alternatively it might just be a broken or poor quality mixer that isn’t providing the appropriate ‘nuance’ of control, and that may indeed be expressed as some sort of non-linear relationship.