Caught up...
Reading the "Why Does He Do That?" book by Lundy Bancroft reminded me every page of my sister.
She has to be superior period. I suspect npd, and codependency.
Anyway, if your brother is npd then I believe the foundation of dealing with him is to understand that he will never change. So you change how you deal with him, for which it sounds like you have an understanding. Good for you as it does take a lot to get to this point, doesn't it?
Whether you decide no contact or low contact, imho, I think it is a question of becoming emotionally detached. The interpersonal connection can be eroded to the point that you have no empathy, sympathy, or feeling for the person...as if they were a total stranger, or a nodding aquaintance (I think of a check out person at the grocery) that you can exchange a few superficial plesantries (never anything personal!) with then move on mentally as well as physically.
This detachment will allow you to choose to 'not listen' to him. I used to be horrorfied that people would blatantly not listen to another person talking to them, but the choice is there for a reason. If you don't want to put the phone down, (in your example it was the right thing to do), you could just start cleaning the kitchen floor, or do something else while he is talking 'at' you, because he certainly isn't talking 'to' you, iyswim. When he understands that you are not focusing on him, he should move on. This is something my sister would do to me, but when I did it to her- she was highly offended, of couse.
Try to get to the point where contact will produce a "So what" and no further detox session is needed.
For some circumstances, this is impossible-so the full no contact is justified. It is justified in the name of maintaining your mental health.