I went from homeless to millionaire in 7 years, no inheritance, lottery, etc.
This was from 2015 - 2021
Got a job in construction, but in a different city. Moved for the job but rent in the new city was high, so I lived in my vehicle and had a Y membership so that I'd have a place to shower. Nobody I worked with knew I was homeless, but I was saving mad cash as I had almost zero expenses.
The highest earning people on our construction sites were the mechanics who fixed the heavy equipment, so I watched, helped, and learned as much as I could from them until I could get a job being one. Spent most of the money I was saving on rent to buy tools.
Once I got a mechanic job, I was constantly in a panic to figure out what was wrong with things and how to fix them before my bosses figured out that I didn't know what I was doing. Visible enthusiasm goes a long way towards distracting people from your other shortcomings. Confirmation bias is real, and if you can get people to like you, they'll focus on your successes and dismiss your failures as flukes. When I started, I literally didn't know where to find the engine in an excavator. That's how little I knew. I was binge watching Big Fix Alaska at night trying to learn how to do my job. Over the next couple of years, I did learn, and I got pretty good at it. Specifically, I got good at figuring out what I didn't know.
By the time covid hit, I had some money saved up. For me, and all of the other essential workers I knew, nothing had really changed. We were still going to work as normal, etc. so I didn't think the world was really ending. So, when the stock market crashed, I bought a 3x leveraged s&p500 etf. I figured if I was wrong, and civilization really did end, money wouldn't matter anyway, but if it recovered, I'd make a lot of money... and that's what happened.
Fast forward to today, I'm still fixing heavy equipment, still working 60+ hrs a week. I'm now far more conservatively invested, but anticipate that in about another year, I'll have enough saved to live off of the dividends, though I'll probably work a while longer to have money for fun stuff beyond just the essentials.