Shiite population is pretty concentrated around Iran and Gulf.
Sunnis have a wider spread and more diverse denominations.
Think Catholic/Orthodox vs Protestant.
Not the same. It would be comforting if it were, but the analogy doesn’t work.
The problem is that Islam, based on the teachings of the lunatic Mohammed, is the basis for both Sunnis and Shiites (I guess you’ve forgotten how the Shiites tried to kill our troops in Iraq) and also for the Sufis and whatever is the Kurdish form and all of the other forms throughout the world, such as the loonies in Sub-Saharan Africa.
Christianity is not a vicious system of domination that wants to be both the civil and the religious law. But that’s exactly what Islam - any form - wants to be.
They may disagree among themselves briefly, but they’re all members of an insane death cult. ISIS is not Sunni - it killed a huge number of Sunnis in its initial incursion. Why? Because they were normal human beings who wanted to have a modern secular civil state.