This depends. But based on how much I have, one of these:

Open a small bar/tapas place in my neighborhood.

Travel

Do what I do when not working - garden, read, exercise, take care of the land & the animals, go see live music.

I have ADHD and my hobby is collecting hobbies. I don’t typically get bored. I would likely need to do some side gig to supplement buying things for new hobbies.

I'd travel, try new cuisine, and I'd also pick up jobs for short stints to pick up skills, almost like journeyman apprentice, I'd also do some kind of social work, and go back to academia with the intent to actually learn and not just to get a degree and get a job, but to potentially do some actual research and development

make art

If I were rich Id open a "Nerd-pub" board games, tabletop games, arcade machines, pool tables, pinball machines...

If I were just "doing ok" id probably start a youtube channel buying really cheap cars of FB marketplace and just reviewing how much of a piece of shit I've bought this month.

All I want to do in life is make music, woodworking, and gardening for food. I would do that until I expired with a smile on my face.

Id probrally learn programming and become a Linux distro/software maintainer for projects like Debian and maybe Libreboot.

Make and restore furniture. Build shit. Garden. Read. Organize and fill out my media library. Learn programming and try to fix some of the problems I'm dealing with on Linux. Probably socialize more because I wouldn't be tired of dealing with people and stressed out from work all the time.

Today being labor day I would go down to the protest downtown, instead I'm going to the office to do as little work as I can manage, maybe have a couple meetings to slow other people down today too

Short answer: work less.

Long answer: I actually enjoy my job, and have for a long time. If I had won several million long ago I would have kept my job because it (most of the time) was very fulfilling and important, though it has largely wrecked my body.

Now I can't fly anymore, so while my job is still important and fulfilling, it's not nearly as exciting, and I am constantly crazy busy, so I'd love to cut my hours about in half, probably. I'd still want to work.

Oh, and I'd build a forge in my backyard. So maybe work the same amount, but some of my time crafting things.

I’d sell all my things to just travel. Living in one place and being stuck in a routine is like a mental prison for me.

Write, program, cook, maybe have sex

Volunteer at a rescue centre to help the dogs and other animals

When the weather is good, be outside as much as possible. Do more long-distance, or even multi-day treks. Dick around in the woods more (survival skills for fun, learn more about identifying local plants and fungi, etc). Bring a book and some basic snacks, and hang out in public park space more often (we've got some beautiful spaces here). Basically just a lot more exploration, primarily on foot, bike, or skateboard depending on distance and energy level.

When the weather is crap, spend more time keeping my place in order and looking nice. Listen to music, read books, maybe try and get more deliberate about a writing habit. Pick a public indoor space of some kind and become a regular. Maybe volunteer.

Spend more time working on good habits to keep the energy level up for the above long term.

Write, read and analyze literature. Hopefully I’ll be able to do it as a job.

Making furniture with woodworking or maybe kitchen utensils with blacksmithing.

I work in cloud tech. Pretty good at it.

But I feel like I should be doing something with my hands. Like woodworking or blacksmithing.

I live in a apartment so I don't have the space to even try out hobby stuff. It's also expensive to do either.

I settled for electrical stuff and bought a bunch of gear to learn soldering. Playing with breadboard is interesting but I enjoy the soldering more.

Build Legos and Gundam models. Finish writing my novel I keep restarting. Hold more Hunter: The Reckoning sessions for the group I Storytell for. Game, work my way through my backlog. Spend more time with my wife.

Enjoy it

I’d be a teacher

I'd grow food. Good food, and way more than I or my family could possibly eat. I'd also grow beautiful, ecosystem-supporting native plants. I'd offer to do the same for my neighbors who dont enjoy such things, or who just want a beautiful and functional yard.

With my leftover time i'd go hiking a couple times a week, and I'd read scientific literature when the sun goes down.

Run an animal sanctuary and grow lots of veggies and flowers

Learn shit.

I'm there. I'm hanging out with friends, spending time in nature, I have a few hobbies, and the rest of the time I'm summoning the wrath of the gods and goddesses to smite the corrupt powers of the world.

So, I'm pretty content.

Start painting or some shit idk

Organise more and better LARPs

First year I'd definitely visit all Formula 1 Grand Prix.

Travel, learn culture science theologie languages and so much more, teach

Acting and singing. Studied Musical Theater in my twenties but couldn't see myself making a living at it.

Make music, perform music, make games, make movies, write small books and maybe draw pictures.

And then I would try out being a research attorney, being an EMT, a pilot, maybe working with NASA at some point and working for some government agency specializing in digital warfare.

People always assume if you had everything you would just sit at home and be lazy and never try anything. But from my experience you don't do that shit just because you're complacent, you do it because either you are way too stressed out to try out new stuff or you are in the middle of a depressive episode. Almost all people I know wouldn't be able to be lazy for more than 2 weeks, they would start making something.

Make stuffed animals and donate them to hospitals, fire stations, and police stations

Organize town-wide scavenger hunts

Learn to cook good food and give it away to people who want some

Start a group that would teach people how to use a sewing machine.

Organize a bearded dragon rescue.

Trim people's hedges

Make videos to share all my knowledge with people for free

Write only free code. Right now, probably 80% of my code is free. I’d bump that up to 100%.

I would find work where I enjoy myself, and get a hobby of travelling the world and documenting cultures

Probably mostly cooking, cleaning, going on adventures with the dog, playing music, and smoking extravagant amounts of weed

Open a non-profit primitive skills school. There are several of these skills that are rapidly dying and will likely be gone within a generation.

I teach philosophy for a living these days.

I’d probably keep doing that, but less of it.

I’d also do a lot of writing.

Continue to work and fuck over poor people is very popular.

I'd make a few kids with my wife, make my private pilot license and travel the world with my family by plane (as the pilot, of course). In the meantime I build aviation related open source software.