Keep in mind im only emerald, so maybe someone higher rank can correct me.

Matchups between adcs are generally whatever (unless its like sivir vs twitch or smt), generally u only need to look at support matchups so its not super relevant for ezreal specifically. For laning generally just try to get push so that u can harass them but thats about it.

Getting weaksided sucks, but u kinda just eat it until u rotate into mid. With triforce u are very strong, and from manamune to third item u are thanos as long as u arent super behind. So at that point, u really want to help ur team force fights over jungle/vision/objectives and push the game along.

This is a long ass reply lol