Easy to do on the Melody and Soloist track.
Alt L>Alt E>Alt L to adjust level of Melody (Melody>Edit Melody> Adjust Level) can set the level up or down by a fixed amount.

I usually set mine to the max (127) then down to what I want. This ensures that all notes are the same level regardless of where they started


BIAB for Windows Version 2019 (643)
Windows 10 (1909)