"The Crown Estate is a collection of lands and holdings in the territories of England, Wales and Northern Ireland within the United Kingdom belonging to the British monarch as a corporation sole, making it "the sovereign's public estate", which is neither government property nor part of the monarch's private estate."
"The revenues from these hereditary possessions have been placed by the monarch at the disposition of Her Majesty's Government in exchange for relief from the responsibility to fund the Civil Government"
"Historically, Crown Estate properties were administered by the reigning monarch to help fund the business of governing the country. However, in 1760, George III surrendered control over the Estate's revenues to the Treasury,[5] thus relieving him of the responsibility of paying for the costs of the civil service, defence costs, the national debt, and his own personal debts. In return, he received an annual grant known as the Civil List. By tradition, each subsequent monarch agreed to this arrangement upon his or her accession. However, from 1 April 2012, under the terms of the Sovereign Grant Act 2011 (SSG), the Civil List was abolished and the monarch was thenceforth provided with a stable source of revenue indexed to a percentage of the Crown Estate's annual net income (currently set at 25%)"
As the crown estates were originally in the private and total ownership of the sovereign, getting three-quarters of the income from them is a pretty good deal for the country.
Perhaps you would like to revert to the previous arrangement, where all of it went to the monarch who then paid personally for the running of the state, and raised whatever taxes they wished as a one-off whenever the expenses were more than the income, or when they decided to go to war with another country? You would then have to bear in mind, of course, that he/she who pays the piper calls the tune.