Does anyone else feel a cognitive decline happening in the past few years? If so what are some things you're doing to help stay sharp?

Title really says it all, I'm in my mid 30's but I feel far less intelligent than I was 10-15 years ago. Definitely wiser, but I just don't feel as smart. I'm not a dumb person, also not a genius. Always saw myself as a middle of the road type guy, highschool through college just a solid B student.

I've significantly cut done on my screen time, started reading again (fiction/nonfiction), reduced video games to a 2 nights a week.

What are some other good ways to stay sharp? ( I feel old just asking this )