Fixing a movie with one tweak

I love this YouTuber by the name Nando v. Movies. If you haven't seen what he does on his channel I strongly suggest checking it out. STRONGLY. Anyways he goes into a movie and tries to make one change (sometimes minor, sometimes major) to make a better overall product. I was wondering if anyone had a movie(or series) that they could tweak ONE thing about to fix/improve.

I'm gonna take the low hanging fruit here. Avengers Endgame (although that bit with the football Nando commented on was perfect) I would have changed the story around Black Widow. Essentially I would have made her and Hawkeye into a team of assassins. Would have still got the Ronin bit in there, but also would have shown that Nat fell back into her old KGB days. Captain America could have gone with them to help get them back on the right path, or maybe reveal something about BW's past that would have made us actually care about her later sacrifice. Everything in the movie around her felt tacked on, and the Avengers didn't even really do much to honor her... they just kinda moped around beside a lake then HEY they magically don't care anymore!