Since its inception, Marvel has always prided itself on keeping all of its projects and plots connected. In a recent interview with The Direct, She-Hulk's head writer Jessica Gao discussed how the show fits into the MCU timeline.
Gao confirmed that She-Hulk would be set "after-post-Endgame" to ensure that all the storylines match up. Marvel has a whole team dedicated to tracing the timeline of everything in their universe.
“It’s definitely after–post-Endgame. There actually is a Marvel person whose job it is to trace the timeline of everything. And we checked with him a lot about where the timing is. And so it’s like…the show is a few years after Endgame.”
During an interview with Entertainment Weekly, director Jon Watts let it slip that there is a "scroll" detailing all of the events within the MCU. “There’s an actual scroll that they unrolled for me… one of my producers, Eric Carroll, it was his first job at Marvel to work on a timeline and see where things line up and see where things didn’t quite line up. Like, ‘Oh, that’s when Captain America is born.’”
Marvel fans will understand how crucial it is to maintain the continuity of their movies and TV series. Following the Spider-Man: Homecoming title card blunder in July 2017, Marvel executives have learned from their mistakes.
Avengers: Endgame would not have been possible without a well-organized timeline. With the Multiverse saga expanding to include more projects, a timeline keeper is now more necessary than ever.