I think that also many do not realise the vast amounts of public money they are given and for what?
A very large chunk of that goes on the upkeep of those palaces and castles (over 50%), which otherwise would have come from the public purse in another way or from a different budget. And for providing the facilities and hosting state events e.g. visiting heads of state - they want to have a state visit with the monarch, not just a Prime Minister (even Trump), garden parties. You can see the full Sovereign Grant accounts for 2022-23 here . Staffing is another big cost, and the staff aren't there mainly to service the members of the Royal Family but the properties themselves so would still be needed to maintain places like Windsor Castle & Buckingham Palace.
You also have to bear in mind that back in the 18th century a deal was agreed whereby the crown estate properties became the responsibility of the Government with the monarch getting a "cut" of this - until then, the monarch paid all government expenses out of their own pocket.
I'd like a smaller role, certainly nothing that is in theory political.
They have zero political power now anyway
And make everybody else pay for their own security, even on engagements.
Ah, so you expect them to carry out official functions without any protection? Sort of like expecting people who work in hazardous conditions to supply their own PPE.
Keep the castles as tourist attractions, give Will, Kate and the two others twelve months notice to vacate to Balmoral, where they can live out their days in obscurity.
And Sandringham, and Gatcombe Park, and Highgrove, and a few others mostly (but not exclusively) in Scotland. All of which are privately owned by the family.