After looking at you project I see you are using a VGA to RCA convert so I decided to check the idea out as standard RCA video does not give the best picture.
So I found a Connector diagram and well as I suspected the screen has RGB input on it which would be used to feed in things such as a NAV unit because it requires more detail.
Here I have atached a copy of the diagram I found and if you get someone to do this it will give you a much better picture quality.
The yellow is how you are connected now and the red, green, blue, grey is where I will be connecting mine.
I also added an image of the addapter cable
Also as a side note get you hands on a Joycon so you can use your steering controls in pc mode as well.