I have been involved in a number of business start-ups, sales, purchases, etc.
Rule #1- Don't buy a job.
Yes, this is often what I tell people when they ask why I don't buy a bigger web business, or quit my job to buy more businesses and run them full time. If it needs my full time constant attention in order to continue making enough money for it to be feasible for me to quit my job, it doesn't seem to be much different than my full time job other than losing the stability of having my paycheck come from a billion-dollar organization!
But that's what I'm looking for... a job that allows me to also get a higher return on a portion of my investment funds. I also think I kind of crave that instability. I have no dependents, low expenses and want to take a risk by jumping into something new. I like challenges and learning. My current career, which has gone extremely well so far, has stopped being challenging or interesting to me.
Well, my first reaction is that maybe you should just train for a better paying job, if that's what you actually want to get out of this. That would be a good way to get higher return on your investment as well, by investing in yourself. And thinking that you might like to take something risky is very different than knowing that you don't mind risk.
However, I find it really unsettling and rather contrary to attaining FI that you think risking large gobs of money on a lose-your-shirt situation is super exciting and fun. If you want to go into business, start small and start in an area you know. Otherwise the run-the-cash-over-with-the-lawnmower scenario might be faster and net you the same outcome.
Think about a business versus a rental house. If you put 20% down on a rental house and the house's value declines 20%, it should still be a good investment (assuming you bought it under good metrics) and you're able to cover the mortgage by continuing to rent it. It's unlikely that the house's decline in value would cause it to bring in significantly less every month to the point that you would have to sell it for a loss. If you can keep it rented, even if you can't get the prices you used to, you should still be doing okay - zero cash flow or above. There's something of a floor in rent decline (ie I could probably rent any 3 bedroom shit hole around here for $600.)
But in a business, the floor on revenue is zero, and the amount of revenue it brings in basically determines the business's worth. So if the revenue declines precipitously, for whatever reason, the business becomes worth less and less. You stated that you have a down payment saved - so you are intending to get a loan - so if you screw it up, and the business loses value, and you aren't bringing in enough money for you to live on, or enough to cover the loan, you won't be able to sell it for enough to pay off the loan. And then you get screwed. You've lost not only your down payment but your livelihood, and are also saddled (most likely) with either a suit filed by the bank to recover that money, or a huge 1099 for the written-off debt. You might have to declare bankruptcy. (Trump has, several times. It's hard out there for a pimp.)
That is what risk in business means. It does not mean "I might lose a little money." It's very different than a risky stock going down. If you start with a big, expensive business that you know nothing about, you could lose everything outside of retirement funds and have your credit affected for a decade at minimum. I am almost kind of offended that you think this is fun and exciting. I am pretty sure you are offended by this post but I am offended by your la-di-dah attitude.
Now, don't get me wrong, there are lots of upsides. You could do very well with it and make more money. But if you're going into a scenario that you don't understand at all, the risk is much higher FOR YOU than it would be for someone who knew what they were doing. So a situation that might be sold as low-risk could very well be high-risk FOR YOU, and the odds of YOU losing your shirt might be much higher than if someone else was in the same situation. Where you really make money in business is where you are very aware of the risk and have the skills to deal with and mitigate that risk. Then you can get a better deal because it's not as risky FOR YOU, and you end up with a higher ROI than someone else who didn't have the skills you have. It's like insider trading - what you know increases the value to you, and lowers its risk, without increasing its price, thus creating a higher ROI for you than for someone else.
But I think you are not differentiating the meanings of "excitement" and "risk". A new adventure is exciting. Learning new skills and expanding your knowledge is exciting. Intentionally seeking out a risky situation, by putting thousands and thousands of dollars into a scenario that could potentially cause you to lose all of it, plus your sanity, free time, etc, should give you no small amount of pause. The propensity for losing your shirt shouldn't seem exciting and fun if you want to keep your money and not go bankrupt.
TL;DR: If you want to own a business, buy one in cash for less than $20k, or start it yourself, in an area you're familiar with, because learning new things is exciting but going bankrupt looking for adventure is dumb.