
I don't think even an adult Cocker would be happy with these circumstances. They have been selectively bred to want to please people and hand in glove with that comes a strong desire to be with you. Left alone for such long periods they could very easily become destructive or noisy. Even if you are lucky enough to find one that reacts by just shutting down and sleeping all day, from a long time experience of the breed, I can tell you this is not a happy existence for them.
As you rightly say you can't properly care for, train, or meet the social needs of a puppy with these hours. There may be other breed adults that could be considered some people say the greyhound is a suitable dog in such circumstances but I don't personally know.