You need to consider the value of your time in a venture such as this. The Hydro Press makes one process at a time, and it's not like a punch press, which works fast, because it doesn't. Making/swaging bullets is a multi-step process.
Here's a view of the individual steps it takes to swage a bullet:
https://imgur.com/mXaQI9m
There's also the huge investment, not only in machinery, but in materials. Base material prices are high right now, and the supply chain is slow. The cost of a set of dies for just one bullet will take a lot of sales to even break even, and that's not counting your time. After all, time is the one thing spent that can't be repurchased. With the backlog Dave Corbin usually runs, you might wait months for a set of dies, or get lucky and only wait a few weeks. He runs a small shop, with just a few employees.
I think you need to talk to someone who has actually gone down this path before you start investing money. You might try contacting Jake Wilcox at Rocky Mountain Reloading about it. Just go to his website at RMR and use the "contact us". I'm sure he can tell you how hard, and expensive it is.
Hope this helps.
Fred