I started to turn my hobby into a business 17 years ago. 5 years later it became my main occupation. I don't spend a lot of time on admin, maybe 15% top, because over the years, I made it a strategic game to streamline my processes, and I pay an accountant to help me with the taxes and other similar things.

It's awesome to be paid to do what I love to do. How much time is too much when you do what you love? Just remember to balance your life after your business is stabilized, so that you have other hobbies on your time off. Also, make space for the important people in your life.

Expect to work all the time in the first few years though, so plan accordingly, for example, if you wanna have a social life, weave your business into it. If you wanna take some time off to play a game, bring your partners into the game.

Don't worry, after your business is stable, you will get actual time off.

I suspect the "don't turn your hobby into a business" idea was originally dreamt up by some business owner who didn't want their employees to leave for a better life, and then we accepted it because it seems to make sense. It sure delayed me for years, before I decided to make the big jump.

That being said, I hear restaurants have low profit margins especially in large urban areas, so if you go for it, make sure to keep your costs extra low.

Spend time becoming extremely good at something you enjoy (and that your community needs) and you will find some people with disposable income will pay you to do it, because they want something good And they can afford it.