hi
sorry to be a bit of a downer - but its tricky. The requirements for a rentista visa just got trickier, and you'd need to prove a stable source of income beyond your parents I suspect.
Easiest way to do it would be to enrol yourself on a course here, in which case you'll need your high school certificate and degree, together with your police record and birth certificate. All will need to be apostilled, and then later translated.
Of course, its a temporary measure and you'll need to actually study if you want to continue doing this, but once you get a student visa you will get the right to work legally, and remain as long as you have a student visa.
There's not really an easy way to get a visa, which is why so many people live here as tourists. Depending on how long you think you want to stay here, that might be the easiest option.