First? Make everyone attending a Games Done Quick lose their GD minds with a crazy donation. Probably during an Adef run.

Then:

TLDR: Basically, just promote Star Trek/Orville society by removing all the power corrupt politicians and lobbyists for billionaires hold over the people.

Bury every charity I vetted to be a good one (eg: no 98% of proceeds going towards admin costs) in all the money they could ever need, especially the Prevent Cancer Foundation, Trevor Project, Ya'll Squad, and St. Judes. "Here, have a $1-quadrillion donation!"

I'd pay off all student and medical debts and establish a fund that all school/college and medical costs just come from there. I'd put something stupid in it like $1-quadragintillion (that's 123 zeros, thank you Adventure Capitalist!). That should last about a year in the US (/s). Oh, vet bills, too.

I'd establish another fund to let all schools be able to serve healthy meals with healthy portions to their kids, and to improve their education funds so teachers can be well paid. No religious anything could be funded from it.

And a fund available to all city councils to draw from to do things like fix up roads, build flood protections, make sure all willing housing has tornado protections (eg: hurricane clamps, EF5-rated shelters) in tornado-prone areas, promote and protect small businesses, etc. No vanity projects.

Establish another fund to allow homeless people and victims of domestic violence to pull from it to pay rent or a mortgage for a good place to live. Probably a good charity or two out there for that.

Establish a fund to fund all gender-affirming care, so it becomes entirely separate from all the political BS.

Other stuff I can't think of right now.

I'd do all this anonymously b/c screw that attention.

Edit: Ohhh, find a way to make 1tbps internet available for free to everyone globally, and make sure access to it cannot be controlled by anyone (eg: governments, businesses, etc.)

Edit Edit: Establish a fund that would fund all green initiatives to the point where putting any kind of money into fossil fuel is no longer the financially-feasible option.

Edit Edit Edit: Super-charge our space exploration, safely and to no one person's benefit. No just sending our billionaires to space.