My iPhone is asking for a screen time passcode that I didn't set

I am try to erase all content from my old phone so I can trade it in and get my new one. I go through the usual process and get to the part where it asks for a screen time password. I had never set a screen time passcode that I can recall and have tried multiple possible passcodes I may have used, is there any way of retrieving this password so I can erase all content?

[Re-Titled by Moderator]