The UK monarch hasn’t failed to ratify laws passed by the Commons and Lords for centuries though and is basically ceremonial.
No. They just get given legislation in advance and tell Ministers how they want it changed for their advantage. eg does anybody think Parliamanet just decided on its own to exempt they Royals from the 2010 Equality Act? Or specific exemptions from the Hate Crime and Public Order (Scotland) Act 2021, or specific exemptions from the Heat Networks (Scotland) Act 2021, or specific exemptions from the Wild Animals and Circuses (Wales) Act 2020, or specific exemptions from the Private International Law (Implementation of Agreements) Act 2020, etc., etc.
And those include exemptions from legislation relating to Planning Controls, Historic Environment, Business Improvement, Tax Powers Act(s), Fisheries, etc., etc.
And some of those exemptions are such that they block investigations into other crimes.
Personal exemptions from over 160 of our laws and those exemptions generally relate to "... in their private capacity" is not in relation to their Royal duties.