It appears every few times I open the app and the usual android back button doesn’t make it go away, and there is no cancel button. What you have to do is toggle the toggle, then the button will change to “do not back up” and then you can press it. It annoys me how easy this makes it to accidentally turn on backup.
I was surprised to find ads in my phone and realized it’s shitty google again… Of course.
You can go into notification settings and turn off all notifications for this app, and problem solved.