system
Given the following post, respond as if you're commenting on Reddit:
human
[DCAU/MCU] Bruce Wayne and Tony Stark fall asleep in their home universes and wake up having swapped places. How do things change?

Bruce Wayne falls asleep in the Batcave after a particularly long and difficult night. Tony falls asleep in his workshop after dealing with Whiplash. When they wake up, Tony is being held at gunpoint in the Batcave by Alfred wondering who Tony is and where Bruce is. Bruce wakes up in Stark's workshop in Malibu. Pepper wants to know who Bruce is and what he did with Tony. None of their gear goes with them.

How do Bruce and Tony deal with this situation? They are returned to their home universes after a year.
gpt
They probably work to find a solution home in that year after convincing Alfred to claim Bruce Wayne is ill (been done) and Pepper claim that Tony is on vacation. 

Tony goes Mecha Batman to fight crime and advances bat tech energy production and A.I. capabilities.

Bruce goes Brawler Ironman and creates more problem solving and pattern recognition programs for detective work.

Tony comes back and uses the bat track to uncover the Skrulls and Hydra infiltration of Shield kicking off secret wars. 

Bruce goes back and uses Tony's energy revolution to turn Gotham into a mecca and Tony's A.I. to better respond to crime around Gotham and the world.