Best age gap between first & second child?

Just curious - I’ve heard that “2 under 2” is not highly recommended 😅😂 but I’m wondering what an ideal age gap might be?

I’m thinking that if we try for a second, it will be when my first turns 2. So that hopefully he will be about 3 when the second one is born (and I’ll be 37, not sure that I want to go beyond 37)

Anyone have an age gap that they recommend?