Warning! Major End Game Spoilers Ahead!!
Okay, so you watched it.
Big thing to see here notice here is the introduction of the multiverse in the MCU. Yes, it was introduced in Spider-Man: Into the Spiververse, but that was Sony and an over different set up.
This is the multiverse in MCU! That means there are other versions of our heroes out there. MEANING, recasting Captain America/Steve Rogers and Iron Man make is totally possible. With End Game making a BILLION dollars in its opening weekend, did you really think they would leave Iron Man and Cap out of the movies? Not a chance!
My Prediction: A new Steve Rogers and nee Tony Stark by the end of 2020!