Android Auto is now my default Android launcher, even outside my car

That car wasn't mine, but I hadn't quit using Android Auto on my spare phone even though my car supports Google's system.

I don't use the spare phone running Android Auto for navigation when driving my car, since the built-in system always works better.

Instead, I now use the spare phone running Android Auto outside my car.

I've used a spare phone for this, but you can repurpose an old tablet to run Android Auto outside your car.

Even the call screen doesn't show up when someone calls me on my Android Auto phone.