Had to restore iPad to factory settings. After hello screen it asks for a 6 digit code that I never had. How to work around?

As described, you have likely restored a backup of your device - upon which a Passcode was previously set.

Much of your iPad’s advanced functionality simply won’t work unless a Passcode is intially set - such as TouchID/FaceID and Keychain stored passwords. For this reason alone, it is almost certain that a Passcode has been previously set, even if the auto-lock function was subsequently disabled.

I summary, you can’t work-around an unknown Passcode. Your only option is to return the iPad to factory settings.

Restore your iPhone, iPad, or iPod to factory settings - Apple Support

What is the exact wording of the prompt - presumably for a Passcode?