Thank you for the input.
For the price and time being, I'll just stick without it. It would be great if Apple came out with a reliable dongle for this, because as we can see, that's not a hardware limitation.
It's sad that I have a mk3.5 Leon with CarPlay, but for me, it's like if I don't have it at all. Using cables on the car with a built in QI charger feels wrong and MIB2 bluetooth calls, music and GPS works flawlessly, why risk more than 100€ for something that won't work most of the time.
The only thing I like most on Apple CarPlay is the fact that you can use 3rd party apps (Waze, Spotify) and a better UI overall, other than that, is just a gimmick.