Check out my young mastiff. They have to be neutered unless they’re going to be bred, otherwise, they have waaaay too much testosterone.
Surprisingly, the raising is a lot like a Dob, keep the dog around you, speak gently, never hit, and they will grow up strong, secure, well loved, self-confident, and an outstanding guard.
Click on my screen name. He was 18 months old there, is now 3-1/2 years old. Taller, heavier, much wider head, but still the same great dog.
I see that he's a "couch dog". My dobies and german shepherd are always on the couch, too. In fact, the dobies will crawl right into your lap.