It's NOT true in practice that you're "twice as likely to get the car if you switch doors" and you are right it makes no sense. This is just a myth that people tell to kids in middle school or elementary school, it's kinda funny you haven't heard or read any of the real theorems yet OP. haha.
The myth is as follows (it's pretty stupid so bare with me):
You make a guess and there's a 1/3 chance it's right.
They eliminate an option and ask if you want to pick again.
The "1st grade level" paradox is that they want you to think that you picked from a 1/3 chance initially and if you were to switch doors it would be a 1/2 chance now because there's only two doors and your first choice was out of three.
Anyone understands that by sticking with your initial choice it's the same thing is being presented with the 1/2 chance initially and just picking any option.
Switching doors DOES NOT change anything in fact check out the simulators, probability analyzers as well as the papers debunking this elementary myth.
It's quite funny actually.
They figured out that elementary schoolers aren't intelligent enough to see through the myth so they use it a lot in movies and shit.