[BerislavLopac]

I think that you're starting from a wrong premise: you would like someone else to create a perfect job for you, that would be stable and secure for a long time with a minimal extra effort -- apart from "just doing your job" -- on your side.

The thing is, startups don't work like that. You need to first find a product-market fit, which means a period (of unpredictable length) during which you have to try many different things, both in the product functionalities and technical architecture, and often you will run out of funds long before you find the right market for your product. There are no "magic cofounders" who will guarantee the perfect combination out of the box, ready for you to sit down and implement it. And even if you find it, you're never "your own boss" in a startup -- at the very least you report to your customers and any investors.

That being said, the good news are that there actually is a type of business which checks pretty much all of the boxes you listed: become a contractor or start a consultancy.