Keeping things simple.
You can’t have an app do this without rooting your phone IIRC. Even if an app like that exists, you can just go to the bootloader and factory reset from there. Some phones allow you to factory reset from the settings too.
But for real though, they had to know that having telemetry be on by default wasn’t going to look good for the open source community.
That entire sentence sounds like a title of a visual novel