What UI/UX Designers do in office besides designing?

First of all, I apologize if the question is off-topic. I am struggling and couldn’t find the right platform nor reading materials on this topic.

How can UI/UX Designer stay inspired, motivated and active during the peak and off-peak season?

Peak Season

As a sole UI/UX designer, I am usually very busy, especially during the early and mid-phase of the product design timeline. However, towards the end; development stage (this could take months), there seems not much a designer can do besides the UI/UX quality check on the staging environment for the new product, updating styleguide and other design documents. I am also spending time learning and reading to improve UI/UX knowledge daily.

Off-peak Season

I also have the same issue about the designer duties when there is no new products in production. While the developers deal bug fixing on a day-to-day basis, I’m not sure what can a designer do daily during the off-peak season. I even offer help to the marketing team for any design works.

Again, I apologized if this type of question is not suitable here. I am hoping if others who have experienced this have advice or insights to share.

Thank you in advance.