My audio levels of the dubbed files are different from each other. Different actors with different intensities

One thing that I am stuck with is that my audio levels of the dubbed files are different from each other. Different actors with different voice intensities.

I submit my films for Film festivals & different festivals have different audio setups which my films audio seems to be immature.

The audio seems very high sometimes & other times too low.
Can you please guide me a little bit on how to get this right ?