If I had Bezos’s money I’d heavily fund cold fusion and high temperature super-conductivity research.
I would also fund boundary layer control for aerodynamics, electrogravitics to a lesser extent — it’s very expensive, and I would fund missionaries to the last people-groups who have not yet heard the gospel [very few of those remaining].
I would invest in shipbuilding because the super-wealthy, then the kinda-wealthy want to retire onto cruise ships.
I would start my own country somewhere.