Applying drag to part of a jump

I’m new to Unity, so I’m not super sure of what I’m doing lmao.

I’m making my character jump upwards using velocity over a period of five seconds, and I want to apply additional drag to my character once the velocity is < 0. I’m having a lot of trouble with it though - either it doesn’t apply at all, or it applies to the whole jump.

// paste code here

screenshot of a text editor

I’m not sure how to fix it so far.