I’m not so sure. The Academy does sometimes award fantasy and sci-fi based on the grandeur of accomplishment.
I remember when RotK won the general consensus was that it was basically winning on behalf of the entire trilogy and what an accomplishment it was. Same could happen for Endgame, you never know. It is, after all, the Producers that accept the award for Best Picture and everyone, including the Academy, knows that Feige has accomplished a ton.