IIRC you can dismiss the three-month trial in Settings and it never comes back.

And IME the app that launches in the car is the last app you had open. Open Apple Maps and then it shouldn't launch Music every time.

Liquid Glass was one person, who thankfully has already left. iOS 7 was the same deal, terrible at launch.

I do agree that the services are pretty bad. Like, advertising Apple's new pet movie through the fucking Wallet app? Should be straight to jail.