A lot of people have been saying that the post Endgame MCU lacked direction. I think this, along with the two announced upcoming Avengers movies, is the missing piece of the puzzle. I now see Secret Wars being a full-on Avengers, X-Men, Fantastic Four, the Spider-Men, Eternals, Guardians, you name it team up.
How do you go more epic after Endgame? This right here.
And realize that Kevin Feige has had a hand in the development of pretty much all of the things that he has brought into the MCU. He was there when they were developing the X-Men and Spider-Man movies. As Marvel Studios president, he's given notes on every Marvel-related project done by other Studios. This is starting to feel like a culmination of not only another epic saga, but of his entire career with Marvel.