Most puppy classes are fairly unstuctured. It's because the point of the classes is the socialization, car ride, out with other pups, new people.
If you go thru those classes and you continue with a comfortable stable dog, then moving up to more advance classes are easier. If you pup freaks in puppy classes then you'll have issues maybe forever.
Have to add I've been to MANY different classes with MANY different instructors. They are all completely different. Some instructors I click with, others ..... not so much. But I keep looking until I find the best for my skills and abilities that help my dog. And since I currently drive over an hour to classes, I know that it's worth it.
I can have my dogs off leash and know they listen and get the exercise they need. So classes do work