Looking busy at work is acting. Being useful is the job.

Appearing occupied is a skill that develops independently of doing anything valuable, and in some places it gets rewarded just as well. The cost lands on you, because a performance builds nothing you can carry to the next place. Visible effort and real contribution drift apart quietly.

Ask at the end of a day what would be missing if you had not been there. If the answer is thin, move some of the effort toward something that would show. Being useful also happens to be the more restful way to spend a shift.