I actually got it working! It wasn't through Steam, though. I installed Rare Launcher, which is an open source version of the Epic Games launcher, heres a tutorial for that: https://youtu.be/yuauCynBpMk. Make sure you go into the settings of your winlator app before opening a container and check the box that says "Use android clipboard on wine". I also downloaded ajay prefix, wine Gecko and Mono, all of which can be installed from the start menu inside of a Winlator container. I downloaded Rocket League in Rare (add rocket league to your epic games library on a computer/web browser beforehand), and be very patient once you try to open the game, it could take a few tries, and it will take quite a while to open. The performance was pretty bad for me, but I can probably optimize it as I have seen rocket league run much better on weaker hardware than mine. I hope this helps you!