He was (but not always, as I’ve learned). He first appeared in 1963 and had his own comic, Nick Fury: Agent of S.H.I.E.L.D.

https://en.m.wikipedia.org/wiki/Nick_Fury,_Agent_of_S.H.I.E.L.D.

And yes, agreed on Simmons and Jackman. Also, we obviously can’t forget RDJ as Tony Stark. An actor so perfectly cast, he basically launched the entire MCU. If it had been anyone else in that role, I feel confident in saying that it would’ve fizzled out long before we’d ever get to an Endgame.