Own enough of the situation to create movement.

You do not need to own the whole situation, and claiming more than your share is its own kind of distortion. What you need is enough ownership that something can start moving, which is usually a modest amount. The goal is motion, not a complete assignment of responsibility.

Identify the smallest piece you could take on that would unstick things. Take that piece and leave the rest. Movement tends to change the situation enough to reveal the next piece.