I would extend that and just say all first party operating systems are shitty

Up to now, I believe, these systems were not first-party but built by the manufacturers of the infotainment systems. Now, Mercedes is taking this in-house to get it right and integrate it with the rest of the far more properly?

BMW’s is alright IMO. Unorthodox in its layout but it actually works well with the center console knob thingy and has historically been low-latency even back when every other manufacturer had a 2 second delay for every action on their awful touch screens.

Of course even BMW’s system is still going to end up being an overly expensive Android Auto/Apple CarPlay launcher because what people want is Waze & Spotify, not random traffic updates from last week & DAB.