You don't need a degree to open a business. And mostly it's for learning things for your own satisfaction, which I sense is what you mean?
It gets more complicated in the US because of unions. In many places, you can’t become a plumber or electrician without an apprenticeship, which is controlled by the trade unions. Therefore, community colleges might offer classes on plumbing or electrical, but there’s no equivalent to a certification program, because it’s not possible to become a professional just by going to school.
This source [0] says “non-dentists cannot set up or buy dental practices as an individual or partnership but they are permitted to be shareholders of a limited company which owns the practice” and “the majority of directors of that limited company cannot be non-dentists”.
[0]: https://www.plutopartners.co.uk/post/who-can-own-a-dental-bu...
That said, this isn't what most people are talking about when they are talking about starting a business.