My wife and I have been playing Pikmin Boom lately. It’s from the same company as Pokemon Go, but focuses a lot more on the actual walking - there are battles kinda like gyms (mushrooms), but you don’t need to hang around them at all (if you can see it on the map you can join) and you can even be invited to remote ones from friends. The other important points of interest - that are kinda like pokestops - are called “big flowers” and they require walking around them* to activate them, standing there won’t do much.

There are tasks to complete for events or leveling up which directly require certain numbers of steps or indirectly require certain distance traveled at walking speed*

(*it’s a little more involved but that’s the high level overview)