I had > 1m at one point. It was enough not to work. It wasn't enough to experiment with random things without risk. Couldn't buy a house in NYC,SF,LA,Seattle. Would just have to go back to work. Couldn't start a business for a project that required 10-20 people. Couldn't really start co-working space for 20-40 people at current rent prices without feeling like I'd probably just be throwing away a few hundred k.
What I could do is travel. Could also live anywhere for a few years.
OTOH, if I had F.U. money, I would do those things and more. I might hire people to do them. There are 5 to 10 apps I'd like to see exist. Would be happy to pay some people to make them and make them open source, if I had FU money. Would love to start a tech-interactive-art museum the size of at least most major museums in big cities. Would consider funding startups.
I have one friend, x-coworker, that picked a different path than me and made lots of $$$ (no idea how much). But, they invest in startups. Goal is to invest $1 million a year. They visit startups and pitch events once or twice a month. They also have a personal project. Otherwise they travel with their S.O. and visit their adult kids around the world.