Spoilers

Voldemort only killed Snape because he believed Snape was the master of the Elder Wand and Voldemort wanted to be the master. He believed the only way to master the wand was by killing Snape. He expressed regret at this, and when he killed Snape, he believed Snape was loyal to him. This specific circumstance apparently didn’t happen in the alternative timeline.

Why?Voldy didn't find the elder wand?

I think he was alive since Draco killed Dumbledore and Cedric killed Neville.

But Draco wasn't killed too😓