Just choose any of these things and participate with him. You could take him to a bookstore or library if he likes reading. Learn to cook steaks together (or teach him). Play Minecraft together. Have him show you how to knit (or take him to the store for knitting supplies). Watch YouTube tutorials on something he likes.

I get it, I have a kiddo that is super into in ground sprinkler systems and space heaters. Sometimes it is hard to find a way to participate.