Tbh I would start up my own charities and keep them specialised and small so no corruption could set in.
People abuse anything even charities. I'd spread the charity net wide too and try and randomly help over the world.
I'd also love to do surprise charity stuff like when someone popped £50 in envelopes to old people in a supermarket at Xmas...
I would never want a huge mansion. I'd have to live somewhere I felt comfortable at night alone.
Maybe lots of smaller houses? One in the cotswolds, one by the sea... And somewhere larger in London.
I'd probably spend most money on travel and the arts. The best operas, musicals, concerts... Learn to ski....
Visit my charities and make sure the money is being spent as needed.
I do adore lovely clothes, but I wouldn't be going for birken bags...
Buy art... Anything I loved... But mostly my money would go on experiences. I'd like to drive an old Mercedes through the desert (with help team behind me in case of break-down)... Go to Vegas... Go to the jungle with an expert spider handler to keep them Way 😂🕸️🕷️.
Etc etc etc.
My dc would get a more boutique, bespoke eduction. Taught privately how to dance and sing.
Languages.
And whatever they want.... Within reason.
I'd invest it wisely however and once the initial spending was done, the capital would be kept intact. It would be nice in some areas to buy houses purely for tenants who were housing associations...
And who had a hard time renting... I'd make them as beautiful as I could, near good schools... But with strict conditions on keeping them in good order.
It would be nice to try and buy at least one house on a dense estate and do it up, paint it, make it look beautiful....... Plant flowers... Etc.. To lift it up and show others what can be done... I'd also set up scholarship to private schools and unis and drama schools in my df name.