There isn’t. If the Queen ever steps in, it’s immediately a constitutional crisis that threatens the entire legitimacy of our democracy. Her role has been purely ceremonial for the longest time.

At least this is true for Canada. I have to imagine it’s very similar for the rest of the Commonwealth. Every instance of involvement that wasn’t ceremonial has been doing precisely what the Prime Minister has requested of her via the Governor General, such as dissolving parliament. Which I guess makes that ceremonial too.