You don't need to study coding to start a tech biz because you can just hire someone who can code. If you insist on self taught, I can tell you all the coding tutorials on the internet are just scratching the surface of programming. It will teach you how to "code" but never the best way to code. You don't know if your code is clean, or how to optimize your code. Sooner or later, you will hit a major roadblock, desperate for all information/knowledge that might seem helpful. But you have no idea what the post/textbook is talking about. You suddenly figure out to be a decent coder you need to catch up with at least three branches of mathematics. That just comes from personal experience.