Impossible to generate or change recovery key

Hello I can't find the possibility to generate a recovery key anymore. Its no longer an option on the phone or website despiser that Apple still referring to it in their user guides ... The only option left is to get a validation code - which is not compatible with old phone (only possibility now to connect to iCloud is to provide this RK-xxx-xxx code.

when I put my Apple ID on newer device (iPhone 5) and changed password (since forgot it) I was automatically upgraded to two factor but was never shown a validation code - so I don’t have one and looks like can no longer regenerate it!

Old device will no longer connect as too old to work with verification code and can’t enter new password without a recovery key!