I've found this to be a often in-depth and curious question-

Because sure, infinite money is infinite money - Difference between say, 800 trillion and 2 Quadrillion, doesn't really show up in short term, mid term or long term affairs for someone - But it does at other amounts.

For my choice amount - A long time ago I realized that a Million is still a figurative amount sorta- so I'd figured that an ideal amount would - peg your daily interest, to a million a day with ,say, a 5% interest rate from investments. Which would be 7.3 Billion at the time of this post. (This can be cheated with a higher rate- so for 7% you'd need 5.2 billion($5,214,285,714.000)

Given days in the year, that's the amount that equals - A Million a day (or just multiply a amount by 0.000137 to get your daily amount at 5%) to then allocate towards good causes when you get settled and set up to do so - The only things seriously out of reach would be trying to own multiple billion dollar things , or yachts which seem to be the most expensive thing- though the key is that yachts can likely have a lot of goodies without being a Billion.

AKA, any more- - I can't see in general what anything more gets you(unless you're vying for political sway or whatnot and might run into other multi billionaires) , and bigger projects really, REALLY should be initiatives by countries. Like Space Stations/moon bases/etc- but that is more suitable and really what a country or few ought to fund, not one person.

(Granted it'll be a long time before lotteries see 7 billion jackpots, but that figure seem to be THE figurative amount.)

Sidenotes: Also for math/comparison purposes using roughly Elon's current time worth of about ~440 billion- using the same figures- that = 60.8 million a day. You still don't see a billion a day in interest until 7.3 Trillion, but that feels very hard to spend large, today without taking a lot more into consideration- but you don't need to be a trillionaire unless you're cooking up (lol) Aircraft carriers, and even then you only need to be a hundred billionaire, likely far far less actually since a pet project aircraft carrier wouldn't cost the same as military ones.

What amount would you pick - and more importantly , what would the amount you pick, scale for/allow you to do? What would be possible? And curiously enough - What would NOT be easily possible at your chosen amount?