If I could do anything? Meaning I was immortal, infinitely rich, not held back by any social standards that would normally bar me from being in certain places/doing certain things?
I'd SAVE THE DAMN WORLD! I'd pay for free healthcare for everyone- I have infinite money, I can afford it. I'd stock every food bank in the country. I'd get the homeless off the streets & the addicts off the drugs. Things that would take too much time for me to do by myself? Pay out the nose for it! Offer HUGE rewards for curing diseases, renewable energy, & restoring forests... that kind of thing. Walk right into the middle of congress & tell them I'll pay the whole damn national debt for a re-written tax code and gun law reforms. I'd go to the border and let the immigrants in- you know what, screw that, I'll go to the countries they're coming from & make them safe. I'm an immortal super-being, I can do that- clean the water, fix the farmland, stop the violence- "ok guys, you can go home, it's fine now!"
I can't fix everything for everyone... I don't care how 'anything' my powers are, some people want exact opposite things & I'm deciding that breaking the time/space continuum with paradoxes ain't what I'd doing. But I can sure as hell get people to compromise so everyone can be happy.
And then, for myself, I'll keep a museum of all my favorite things for everyone to enjoy. Old console that never break down becuase I make them never break down, movies and music recordings that never wear out from use, available to all, for free. It wouldn't be a perfect world, but it would be a happy one.