Oh yeah! Let's do Infinity War again, just with more characters. That's a great idea.
Nah, the only way they can do another big crossover event and actually have it MEAN something, is if it's *this*, and if they do a crossover with the comics and whatever TV shows/cartoons they have going on. Do a Spider-Verse, but bigger.
But then, don't actually do that, because that'd be a dumb idea too.
Just stick to the regular movies from here on out. Maybe do one more Avengers in ten more years, but there's absolutely no way to top Endgame right now. Maybe not ever. The best you can do a this point is a lateral move. Best not bother.