Deep deep deep interiority, and only one person, for that one person I serve, the entire story exists for that one person and that person only.
I have tried multiple POV for my old pen name and at the time my worldview was somewhat different, so it was possible. Now as Wynn I was trying multiple POV with the recently-failed WIP, and I think one of the reasons for the failure (in the case of this particular iteration) was the dual POV that I was trying.
It worked very smoothly at the beginning, because the beginning is when I am getting to know these people. It worked really marvelously, actually, in the beginning. You can know character A through character B, and vice versa.
But the more the story progressed, I couldn’t reconcile the dual-master thing. It really did feel that way, like I didn’t know who I was unfolding the story for. I was serving two masters. My current worldview (storytelling view) is very much: if Y happens after X, then it is because the protagonist is the protagonist. Therefore if there are two masters, then there must be a shared reason, one that makes sense for everyone, why Y happens after X. But if so, instantly, the story becomes boring for me. I was trying to reconcile this situation somehow, by trying to figure out how life actually would work if there were two masters, and the simple answer is that it wouldn’t work.
This is the reason no one gets to mess with our individual experiences. No one gets in, very literally.
There is one narrator, one story, one life, all is one, one is all.
When the wind blows in the story, it is for the protagonist.
When the sun rises in the story, it is for the protagonist.
When people die, it is also for the protagonist.
This is also related to why I love 3rd person writing.