I'm still wondering what Vader can do to actually hurt Tony. He's resisted telekinetic attacks before, Vader can't outspeed him, there's a lot of ways Iron Man can counter a lightsaber. Maybe internalized TK to attack Stark's organs, but Vader has almost never used such attacks in-character, especially mid-battle. He primarily focuses on pushes and shoves.
And there's only so much firepower his Force Barrier could take before breaking and at that point Skywalker gets melted.