Now imagine building an online lifestyle business such that after it’s setup you can spend 0 time on it (for the most part) and still earn enough to pay (reasonable) living expenses.

That’s what I’m driving towards.

This is part of the motivation for doing browserless.io for me (though I’m fascinated, still, by the tech and product).

I’ll say that the 0-hour thing is pretty impossible, though you’ll likely not work near 40 hours ever unless you want to. The biggest takeaway I’ve found is that, aside from gaining time, gaining freedom of choice is very liberating. You’ll feel the consequences as well, which I’ve enjoyed overall (even the tedious stuff can pay out in dividends).

It’s definitely worth pursuing, but does come front-loaded with work and a lot of time spent

That sounds fantastic and it's something I aspire to achieve; however this falls into the category of "should I laser-focus on this, or have a better work-life balance?". Part of my difficulty is figuring out the tradeoff of "sacrificing wellbeing today to build a solid foundation" vs "do not postpone enjoying life".

is there a list of these kinds of businesses out there? What is your business gonna be?

There are some passive income subreddits where lot of folks are very into this. You might get an idea there.

That's a great way to think about it. Thanks for the insight :)