I'm no way near to be an expert on this topic, but I can share some experiences that we have gone through. Nikita is my 1st Doberman and I wanted to do the best, but I soon learned I had a lot of learning to do, even about my self. Dobermans are very in tune to their owners. If you are in a happy mood, they pick up on that vibe and they are happy too. If you had a bad day, they pick up on that and it seems to confuse them, which usually leads to unwanted actions that just adds to the situation. For example, when we were working on loose leash walking, it was bad. She did not do it right, I started to get aggravated, she picked up on that vibe and we just spiraled down hill from that. I thought we could just keep doing it and she will get it, but because I was giving off the bad vibe, it never worked. At the end, both of us were frustrated. Once I approached this with a calm attitude, we were able to start making progress. It was a slow process, but it worked
As their Pack Leader, I learned two important things. You do not need to dominate and they need to know that you will be there for them. Let me try to explain. I was a little hard on my girl, thinking that if I barked out orders, she should obey, now. It didn’t work. When I was calm but firm, she responded better to me. When I yelled, she would get scared and she would not listen at all. All she wanted to do was get away from me. By being calm and firm, it was like, Oh, you do not approve of that, I will not do that. That’s kind of simplified, but hopefully this makes some sense.
They need to know they can count on you as a leader to protect them. When she was in a situation that scared her, she would look to me as a protector. When we started to go to a local dog park, she would occasionally get her self into a situation with another dog that was unpleasant to her. The other dog pursued her, growling and snarling. She was running away crying/whining to get away from that dog. Once I stepped in and stopped that dog, politely of course, I checked out my little girl to make sure she was alright (no bites/wounds). I did not make a big fuse about it and just let her get back to playing with the other dogs. This action let her realized that she could count on me when in an unpleasant situations. I would not make a big fuse about it because I did not want to encourage that if she was scared she would get lots of attention. I just stopped the incident and we move on.
I have learned a lot about myself by being with my Nikita and also about her too. I know what situations make her uneasy, but she has learned to trust me in these situations and to know I am there for her. I know this is not totally relevant to your situation, but I found that having this mind set has helped us a lot. I hope this can help in some way. Good Luck with King and I believe its not too late.