If you really want to pick a bone with Captain America’s actions at the end of Avengers: Endgame, the much more significant thing to target is the understanding of his life parallel to Bucky’s through the 20th century. He can’t do anything about it because he can’t screw with time, but Steve presumably lives his life through the 1950s, 1960s, 1970s, etc. knowing that his best friend is being used as a brainwashed tool for Hydra, assassinating key public figures (including Tony Stark’s parents).
Article source: https://www.cinemablend.com/news/2489394/did-sebastian-stan-actually-criticize-captain-americas-ending