I'm unhappy with the audio tracks' volume inconsistency

I'm happy with the exercises/topics/scenarios.
The only thing I dislike is inconsistency in the volume of audio tracks.
When I listen to a record I have to raise the volume because it is too quiet. But then, the next track, I have to make it quite because too loud.
I usually practice using my over-ear headphones and these volume differences are quite noticeable, making me keep my thumb on the volume controls of the phone.
Could you normalize the volume of all the audio tracks upfront or integrate a third-party library for volume auto normalization which makes too quiet audio tracks - louder and too loud audio tracks - quieter.