If you're not eating anything else, but still have a year-round growing season, it takes an acre or two for modern agriculture to feed a person. That's a lot by city standards, but not in general (it was more like 60 in pre-modern times). It's basically what the Ethiopians mentioned are doing, plus the cocoa so they can have things that don't grow on trees, as well.

and will like 30min of effort a day you can have more than enough for your own needs.

Mountains of human experience suggests it takes a lot more effort than that. Have you had to deal with pests, drought or disease yet?

You might still come in under 8 hours a day, but then you add in the cash crops... Again, this is something only white people generations away from subsistence farming seem to think will be easy.