[Timelines are dumb, everyone knows this, especially someone named Leia who is also currently trying to change her future timeline. But that last bit is something Ezra doesn't need to know. He may want to stay in the dark about most other parts of the future, but leaving him with just Alderaan and not the knowledge of what happens to the Death Star is cruel.]

We do destroy it. There's a story behind it I'd be proud to tell if you were interested in learning it, but the end result is the destruction of that abomination.