That, or you’re going to need a shit ton of superpowers to try and subdue her in the least.
For the sake of this exercise, we’ll say that Jean still has some of that power within her, enough to be a massive threat to the world.
Luckily, Tony can find both.
While the Dark Phoenix can still be reasoned with, as Jean is still very much a part of this phenomenon, it’s a task that should only be approached by those who have the most skilled finesse in personal dynamics.