I think them learning to be alone, is a little tougher on the ones that have someone home all the time. I’m retired so I can run into the same problem. If I know there is nothing that they really need. I just crate them, and take a shower, or whatever else I need to do. Yes, they can throw a little tantrum at times. Just try to wait until they stop. Even if it’s just a few seconds. Most of them learn the barking does not get the desired outcome, and they stop. If we run to them every time they bark. We are training them barking gets them out.