Not sure if this helps , but I find with my red setter, if I give food high in carbohydrates it makes him hyper and unsettled.
I have just looked up what beagles are like on 101 beagle dogs on you tube. It does say that they are hard to train , but they like their food so may be get some lovely treats.
I have looked after lots of puppies with guide dogs, and I know that it can be hard work when training them not to wee indoors etc, but do not be to disheartened he is only a puppy and one day he will get it the next it will feel as if all the work has gone out of the window. Keep going be patient and you will win through.