The trapezius can practice in one direction, and the dumbbell can shrug. I think I have to pull back and pull up. If it really doesn't work, when you do barbell shrug, your mind leans to the weak side:)

Suggestion: back+both ends+oblique side, put it in a day's exercise, of course, mainly back. After practicing both ends of back, the oblique side will play a "warm-up" role and the effect will be better!