I was trying to remember where in the timeline Ultron occurs, before or after Chadwick's introduction, but it was before, just pretty cool how Banner at first couldn't get say Wakanda correctly, and then we get a whole movie about it. It was also pretty cool that Captains fears get somewhat played out in Endgame, and while it didn't seem that big of deal to him in Ultron, it's a story line that played out in Endgame.
BTW, just read an article today, and I don't think it's really a spoiler, but sorry if some find it is, but Randall Park is the guy on the radio in the second episode asking about Wanda, reprising his role from Ant Man.