Many Mastiffs and Bulldogs are adopted for the additional purpose of serving as a guard dog as well as a companion. Guard dog training can actually help your dog learn to become more disciplined and well behaved, very much in the same way that obedience training can. If you think this activity would be a good fit for your dog, then check around your area for reputable guard dog trainers near you and talk to them about guard dog training further.
American Bandogges can benefit from being taught new tricks occasionally in the same way that any other dog can. If you'd like your American Bandogge to be able to sit, stay, lay down, or roll over on command, then set aside some time every day that you can dedicate to teaching one of those tricks using a treat and simple commands.