You need to make the tutorial mandatory for every future beta testers invited ! The amount of people who don't understand the basics is almost scary. Before even starting matchmaking, first thing I did was search how to switch to solo, then did so, then did the tutorials and ALL the missions before even considering matchmaking. Then when all that was done I started matchmaking.
Because unlike some of my gamer colleagues, I'm decent enough to know when I'm noob at a game, and when I start a game I never ever played, I know I'm a noob at it. And even my first few games I got a bit carried, because I needed a grasp of the melee triangle and suspicion system. But at least I was not an uncarriable burden for my team.
I'm not trying to be mean to people who start the game, but to be nice to those who know the game. I never player Rocket League's competitive, never even considered it, before my first 300 hours of gameplay
So you see it's not a one way street, I apply this philosophy to me too !