AU where an unmarried, childless Tony doesn’t die but becomes unstuck in time. He has some adventures, maybe soothes his childhood self, whatever you want. But he also visits Steve a lot and manages to work out his anger and hurt (especially since past versions of Steve technically didn’t do anything). As hard as it is, maybe he even tells some Steve that Bucky’s alive and helps him through that revelation, bringing them very close. Eventually he is rewarded for his efforts and lands in a perfect, heavenly timeline with Steve (whatever that may be).