How do you deal with boredom at work?

I have been doing my job for over 15 years. Even though it theoretically could be a different task everyday and used to keep me engaged, now I’m bored out of my mind and every problem I solve feels like one I’ve solved before.

Do I need a new career (let ADHD lead)? Do I just need to structure my way out of this (let autism lead)? Or are there ways you’ve found to inject some excitement so that you can stay in your career?