There may be several ways of doing what you’re after:
-
via a midi insert called Midi Modifiers
automate the Velocity Shift parameter -
via the Midi Modifiers section of the inspector
automate the Velocity Shift parameter -
via editing the velocity lane in the Key Editor
select a desired range of notes where you want to increase or decrease the velocities over that range, then grab the handles at the top left or top right edge of the selected range, and move them up or down as demonstrated by Greg Ondo (he’s got tons of Cubase material on YouTube).