The dreams I have would consume the Bil handily.
Let’s see: my n:o 1 dream is to buy a massive hunk of prime farm land and convert it to an ecological sanctuary. Like here, only bigger: https://edition.cnn.com/2020/10/01/world/knepp-farm-rewilding-scn-cte-spc/index.html?fbclid=IwAR0o3Yw4oRERiiNk8gC-CEXiYGeUYmc-S4jetDwhAnuoXPZltwO4TBV6YSk.
They stopped making land, so I’m looking at a price tag of easily hundreds of millions. Having only 5 years, I would not see the transformation in full bloom, but I would start it, and bask in the glory of actually making a difference, for 5 years straight, and leave a lasting legacy. Also, places change drastically in only a couple of years when mostly left to themselves. Been there.
My n:o 2 dream is to sponsor archaeological work, where there are innumerable study bottle necks the world over, that simple money would fix: robust budgets for massive emergency excavations, AMS dating series by the thousands, Isotope studies, aDNA studies, conservation of wetland finds, lavish publications etc.
I’m looking at a 100 millions easily spent on archaeo. The money would also mean that the results don’t wait for themselves, as per usual. Hire 20 lab technicians where there were 2 massively overbooked ones etc. It would be a constant 5-year thrill ride to have a daily dose of “Another Ancient Mystery shed considerable light on [let’s be realistic here]”.
Dream n:o 3, would be to build and host a experimental archaeology research center, where I would hire thousands of niche experts full time & with open-ended project budgets, to replicate ancient technologies of every type the world over, and publish every result promptly and lavishly. I’d get to see huge progress within 5 years, and spend my days dancing around the vast site like a kid in a candy store. I’d also bleed millions, on a constant basis.
Sure, there might be a spell or two of King Midas-type woes, but the diversity would keep me in an extended endorphine rush. And I could always retreat to my sanctuary, and watch animals taking over.
Of course I would buy a bunch of very expensive toys, but they would fetch mere tens of millions, at best, as would giving gifts to people I care about.
Especially with Dreams 1 and 2, there is no end to the spending, as every additional hectare / study grant / employee would further my goals, no matter how far I’ve gone. Yes, “spending on things I actually use and enjoy over 5 years.”