"Steve literally widens the screen with his hands"? Fine. But a "unique method of breaking the 4th wall"? No, there are plenty of examples of similar things inside and outside previous movies.

E.g. Tony Randall reduces and stretches the screen at the beginning of Frank Tashlin's Will Success Spoil Rock Hunter (1957) (specifically from about thirty seconds to about one minute), and then again at its intermission; Tom Ewell does much the same at the beginning of Tashlin's The Girl Can't Help it; etc. There are abundant other ways to play with aspect ratio and screen size.

IMHO if anything the above examples I cite are far more playful and entertaining than what Dolan does with screen size, which I think is hardly more than a stunt. In the above two examples, what Tashlin does is intimately tied to the experience and meaning of his movies, to movies in general, and to the times and culture.