how do i retrieve a forgotton restriction passcode on an iphone11

If you or a member of your Family Sharing group have a mobile device running iOS or iPad OS 13.4 or later, or a Mac running Catalina 10.15.4 or later, read this support article for instructions on what to do "If you forgot your Screen Time passcode". Click here --> https://support.apple.com/HT211021

If you still have issues resetting your Screen Time passcode, contact Apple Support.

https://support.apple.com/contact

Did you try contacting Apple as I indicated?