I really think you’re making your dog out to be a human. They don’t need dessert, they don’t even need snacks. I’ve almost always had three dogs and I throw away more treats because they’ve gone stale than I use. I’ve never been in the habit of using a lot of treats.
I’ve never had anyone say you must feed dogs enough to be full. How the heck would you know if they’re full? A lot of dogs will eat everything you put in front of them. This is one cause for overweight dogs. The same for humans. I’m overweight but it’s not from eating til I’m full. You should be satiated, not full. How do you know a dog is hungry? Seriously, people say that and I don’t get it. They can’t talk, you don’t know, it’s an assumption.
