Like, since we have a ton of characters, all of whom could creatively find ways of fucking up Thanos, they have to find the sequence of events that doesn't end the movie anti-climactically.

That or, y'know, they have Ant Man shrink it but then it's revealed one of Thanos's guys can change the size of matter too or something. It's like what Rob Lowe's Hollywood producer says in Thank You For Smoking, that anything in a movie can be solved with "Thank God we discovered the Whatever!"