They were at the right house and the bodycam footage shows that they did announce themselves at the front door.
Reportedly the victim was using noise cancelling headphones and was not aware of the police's presence until they broke into his bedroom window.
Now, if I were to answer your question, I would say it first depends on circumstances. I have encountered many people with guns. But if I was and active officer and encountered someone with a gun, I would do my best so that the encounter was arranged in a manner that gave me some advantage and at least a second or two to think before acting. Sometimes, mistakes are made though, and they always will be made. But the fact someone had a gun is no excuse.
Police in many jurisdictions will just walk onto your property in pursuit of a suspect and get mad at you if you open a window or door to see what the hell is going on outside your home.