When Can I Stop Working Full-Time?

In most cases no but you already did. I believe every adult man should follow your example. Quit their jobs, open a Paytreon, then beg for money online instead of work. Like Pokimane does as well.
Or yes you can work part time if you aren't an idiot consumer. I don't use smartphones for example therefore I only work 15-20 hours a week to get by. That's about what? $200 a month service fee? Why are you paying for that? Why are you paying for XBOX Live sub? Amazon Prime when you barely use it? Cable, Netflix, etc. Pirate everything because other humans would do the same to you but they would steal your house if they could. Pirating digital content is fine because it's worthless anyways.
If you're a male then just avoid real females and find free waifu harem. There you just cut 100,000% of a man's typical idiotic spending. Do not accept contracts, loans, or anything like that. If you can't afford it right now you can't afford it ever. Do not travel, go anywhere, just stay home and escape the shitty reality with pirated fictional escapism. This way you won't get harassed and arrested by Gov goon thieves for leaving your home as a male.
Do not procreate for the love of God. Earth is already lost to Evil/Satanic masses worshiping the cults of Govs so God wouldn't want new innocent lives to suffer here on Earth anymore. Bam that saves you the $1,000,000 it costs to simply take the expecting mother to the doctor for the first 9 months.
Do not go to doctors anyways. They are con artists. You won't be any better of than before no matter how bad your health is. You might end up worse with more diseases from their processed fake medical products. Or a nurse will steal your credit card to buy more smartphones and handbags.
I tell ya what though no men can work part time when manchildren and thots keep quitting the workforce to sell worthless e-books and monthly sub plans for memberships. Amouranth does that as well. I'm one of the only men who can still pull it off because I don't get suckered into buying your free dime a dozen content that is all over for free in an over-saturated mess of unemployed working age "adults" who are not truly adults. Every streamer is applying for UBI checks every month and then giving out financial advice at the same time. Cute.