You can get some inspiration from businesses for sale on Empire Flippers https://empireflippers.com/marketplace/.
As a rule of thumb for choosing the niche, pick from one of these https://support.google.com/admob/answer/3150953?hl=en
The work should be strategic. Focus on money. Crypto payments, payment processing, pay walls, take money for something with the design that a little bit of that goes to you. Don’t cheat or scam, that will be your undoing (besides, if you have to be told you’re not smart enough to make that work.)
Or try cashing in on eyeballs. Set up the ad broker accounts, and get some novel quirky content up and keep rotating it.
It isn’t impossible to do, it’s being a slave to these ends which make it shit. Grind. Grind!
Silly uncertain people make millions all the time, you have to live for it (and that has its own kind of suck.)
Good luck!
There is no once and for all solution for anything. Here’s the secret: the whole universe is falling apart and the only thing keeping anything together is someone/something paying for it.
You don’t need the whole pie. You might survive from the crumbs of a thousand pies.
You could read P.T. Barnum’s “The Art of Money Getting” and “The Richest Man in Babylon” to give you some insight into the classics. None of this will help your desperate sense of immediacy.