Obviously I'm gonna work out how much to set aside to live comfortably off the interest forever first. That should not require a big percentage of that much money. Get myself a house, make sure my loved ones are set and comfortable too.
Next I'm going to set aside a chunk of it to be completely irresponsible with. I'm gonna get on a train and see all the bits of Europe I want to see, stay in nice hotels, eat in fancy restaurants, and bring my friends and family along to various bits of it. There are a few things like videogames I would like to see developed but do not have the skills to make myself, so I'll throw a few tens of millions at those ideas. If they work out, awesome, they might even pay for themselves. I've always liked vehicle design so I will get a car coachbuilt. Not something flashy and loud, just something exactly how I decide it should be. A bunch of custom-built guitars.
So with needs and vices taken care of, and I cannot imagine I have even come close to getting through the first of five billions yet, it's time to actually try to do some good. I have a strong casual interest in history, so I think I'd enjoy funding work to be done by local institutions in places that are currently relatively under-explored. Ask universities in these places what they want, ask nothing in return other than that someone shows me whatever cool stuff they've learned every so often. You want to take the time to laser-scan a bunch of ancient buildings like the Zamani project is doing? Hell yeah, I'll pay everyone's wages for that. My thinking here is that if I'm not directing it I'm unlikely to unintentionally fuck something up through ignorance, and by paying for skilled work that is not extracting anything physical I am hopefully giving the local economies a boost in a way that should not result in me undercutting any local industries or anything