How can I earn money quickly from home?

Learn a language, and become a tutor. If you learn Spanish (for example), you can teach English to Spanish speakers, or other way around.

You wanting business, sir?

Invest in growth stocks

If you can't work due to disabilities then surely you are receiving state benefits to support you? 

You can either work or you can't?

Petty cash is like a petty officer, small and insignificant.

You can't. You either have marketable skills that employers are willing to pay for - or you don't. There are no (legal) magic get-rick-quick-while-working-from-home schemes.

Best bet is probably a site like OnlyFans or something similar. And I’ve never heard of people making hundreds of dollars in a few days doing surveys, usually it’s hundreds on pennies in a few days of doing surveys. But steady, reliable, significant income...that’s a job, which you don’t want.

"can't get a job" is not compatible with "earn money".  You either can work or you can't.  

Assuming you can work, then you get skills which companies need.  Data entry, marketing professional, programmer, accountant.....they're all real jobs being done from home these days (even before 2020.)

Sorry.

If there was something, we would all be doing it by now.

There are many work-from-home jobs, especially in the days of COVID.  Of course, we are talking real W-2 jobs so you would have to give up your diability checks.  You could also do things like babysitting, pet sitting, etc.  You could produce something and sell it on a website.

Without knowing your skills, talents, and experience, it is pretty difficult to advise you on a job that might suit you and one that you could do from home.  Do you have a college degree?  Any type of certifications?  Any job skills or experience?