My biggest complaint is that I have to use Siri and can't change it to another AI assistant. I can't use a different launcher, etc. I will openly admit to being a Microsofty (just a user, not an employee) and want to use Microsoft based services like Cortana since all of my information is synced that way. Yes I can use Cortana on iOS, but Siri is always there as the default. With Android I can turn the Google assistant off entirely and make Cortana the default.

I'm fairly annoyed on Android that I can't uninstall some stock Google apps.