Yes it entirely depends on whether they store previously used usernames along with the date range it was in use (to tell apart multiple people who used the same username at different times)
We'll have to see if any unsealed cases in the future support that they don't keep those records like how they don't keep IP logs, but personally their track record is enough for me to have confidence in the feature, especially since my "threat model" is primarily opportunistic hackers or spearphishers at most, not police or state / nation state level actors.
This is one of the reasons I never want a car with it's own internet connection. I'll stick to plugging in my phone, where I'm very stingy with which apps even get location data, much less the "physical activity history" permission which allows this kind of continuous tracking (and which is usually needed because it uses Google's algorithms / possibly neural nets to guess whether you're driving or walking based on accelerometer / gyro / gps / magnetometer sensor fusion).