I do 2 kinds of walks with my dogs, both do no permit pulling. On most walks, I like to use a longer leash and I allow them to sniff and do whatever… it is what is fun for them. On exercise walks, I make them heel and keep head up. That way they get that sometimes they can meander and sniff, other times it's business.
I have never tried it, but I suspect you can teach sniff, then NO SNIFF lol.
We do both on our walks, free leash and then heeling. But I would love him to have his head up more during free leash walking.