That’s not how money works in the UK. The taxpayer isn’t funding the monarchy or anything else. If anything the Crown is funding the taxpayer via the Bank of England.
Except the Royals themselves say something else. You linked to a webpage about how money gets created which isn't germane to the provenance of the already existing money that is owned by the royal family.
Take a look at "the official web site of the British Royal Family. Written and managed by the Royal Household at Buckingham Palace, the site aims to provide an authoritative resource of information about the Monarchy and Royal Family, past and present." [1]
That website has a webpage devoted to the "Royal Finances" [2] that says, "There are three sources of funding for The Queen, or officials of the Royal Household acting on Her Majesty’s behalf, in both a public and private capacity. These are: the Sovereign Grant, the Privy Purse and The Queen’s personal wealth and income."
"The Sovereign Grant: This is the amount of money provided by Government to the Royal Household in support of The Queen’s official duties, including the maintenance of the Occupied Royal Palaces: Buckingham Palace, St James’s Palace, Clarence House, Marlborough House Mews, the residential and office areas of Kensington Palace, Windsor Castle and the buildings in the Home and Great Parks at Windsor, and Hampton Court Mews and Paddocks."
The sovereign grant is 15% of the income from the Crown estates. Depending on who you think owns / should own the Crown estates (it was once the monarchs personal property) this is potentially a big subsidy to the tax payer from the monarch.
Ultimately the origins of most property is tied up in violence, not just that of the royal family.
In the sense that the Crown leases the Crown Estate to Parliament in exchange for a guaranteed income? Sure.
In the sense that that arrangement could be reversed without massive upcry, a constitutional crisis, and the dissolution of the monarchy? Not realistically. The government has de facto control of the Estate, and the monarchy receives a de facto taxpayer-funded income (plus their private ownership through other property.)
Take a look at "the official web site of the British Royal Family. Written and managed by the Royal Household at Buckingham Palace, the site aims to provide an authoritative resource of information about the Monarchy and Royal Family, past and present." [1]
That website has a webpage devoted to the "Royal Finances" [2] that says, "There are three sources of funding for The Queen, or officials of the Royal Household acting on Her Majesty’s behalf, in both a public and private capacity. These are: the Sovereign Grant, the Privy Purse and The Queen’s personal wealth and income."
"The Sovereign Grant: This is the amount of money provided by Government to the Royal Household in support of The Queen’s official duties, including the maintenance of the Occupied Royal Palaces: Buckingham Palace, St James’s Palace, Clarence House, Marlborough House Mews, the residential and office areas of Kensington Palace, Windsor Castle and the buildings in the Home and Great Parks at Windsor, and Hampton Court Mews and Paddocks."
[1] https://www.royal.uk/about-site
[2] https://www.royal.uk/royal-finances-0