Yes? I mean, no, they're not the only bad guy. There are other problems to address too and other ways to solve the abstract problem. But abstract solutions aren't the same thing as "justice", and these officers made the decision to engage in violence that killed an innocent woman. That's culpability, period.
Look: the whole reason we put guns into the hands of special people is that we trust them to keep us safe. And that trust should come with responsibility when they don't. The officer's judgement needs to be applied in circumstances like this, they aren't robots. If they felt, like you do, that the warrant was impossibly unsafe to serve, they should not have served the warrant. That's what the trust we place in them is supposed to be for.
And they didn't. Clearly they were wrong about the safety, but they thought it was safe, because they did it. And Breonna died. And that lapse in judgement needs to be addressed with justice.