Maybe you are trying to explain the Born rule, but I was not claiming to explain that; I've already stated decoherence doesn't explain why we get certain outcomes instead of others.
It explains what we experience perfectly well. In the simple case of a 50/50 coin flip, there will be two equally real future versions of you. One will see heads, one tails.
You don't need to dive into quantum mechanics to understand this concept; instead, consider being cloned twice while you are asleep, then killing the original.
Your current self knows what will happen; you'll fall asleep and wake up as either one or the other, becoming both but never being both.
So Decoherence only explains those things after you already have the Born rule (P ∝ |Ψ|^2). But that's the very thing we are trying to explain!