Track volume controls how elements sit against one another in the mix. Peak level concerns the highest signal levels, while loudness describes the level over time in a way intended to relate more closely to perception.
Invideo Editor includes mixer metering and a Loudness target in Export. Balance dialogue, music and effects first, then choose delivery settings for your destination. A loudness target cannot by itself fix dialogue that is masked by music. Listen to the exported file as a final check.