DX by the time of civil war, peter was a college professor, a renowned scientist and tony was coming to him for help. People died, major changes happened, and it was a huge war. It wasn't a fist fight, at a German airport, that was farted out over the weekend... I HATE THIS TIME LINE!
No... they didn't go really deep and kill a bunch of people off because of their own established time line, and that WAS also their plan for avengers 3 and EG. imagine endgame's plot in a world where they had already tried to kill the entire cast multiple times.