I'd say the only way to succeed at your dream is to actually do it, but at the same time I agree that there's plenty of competition and 3D printing has become so accessible over the last couple of years.

Ive found a little niche of a product that I customize and print while a buddy of mine handles the sales aspect of it. I print them out and sell them to him at a fixed rate and then he sells them to people for at least double what he pays me. He tried to bring in a guy to 'invest' in us but after talking with him it didn't really make sense for what we're doing. I'm perfectly happy to keep things small scale and I've already made enough to cover the cost of my Bambu X1C. I think like others said you can really destroy a hobby by trying to turn it into a business and that's not something I want to experience.

Maybe it would make the most sense to start out with what you have and build the business as needed. There's no reason to start out with 10 printers if you don't have any customers. Maybe start with one and build your print farm out as needed when it makes sense. If you're planning on selling a product and not print services, there's nothing dictating that you need the ability to manufacture high volume immediately. Maybe try printing a bunch of the item over weeks/months and then testing the waters with how quickly they sell.