Welcome to the forums. IMHO, the easiest way to do this is to automate the volume. Set your snap points to the duration you want to lock the level changes to, if that works for the part.
You could cut the clip up and use clip gain for each segment and then just copy those, and, using further volume automation might provide some interesting level changes to the overall part.
Good luck working it out.
P.S. To have your questions answered more effectively, please consider editing the “signature” on your forum profile to include some basic system information – Cubase version, audio interface, DAW specs., etc.