Here are some nice videos I found showing real car factories and how they operate, without talk and narration and sale talk.
Biggest differences I see compared to the game is how the rolling chassis and the body are build separately.
Also how the beginning of the production line it’s all automated and you see little to no humans, while the end of the production line it’s all humans you see and almost no robots.
Mercedes: youtube.com/watch?v=8b6OuTpR9c8
Porsche: youtube.com/watch?v=BbcKZ1lRDuA