TL;DR:

You can be registered in your own company as a manager on the minimum wage, pay a fixed sum of social insurance every month (~100 EUR), and then basically set aside 15% of your invoices income for tax, and the rest is yours.

This is exactly what I do for years, it's not fiction and it's working.

That's very similar to other countries. Slovakia and Czechia. The social insurance is bit higher and scales with income but itsnot like Bulgaria is only cheap eu country.

Never claimed it was, was answering a question with facts to clear confusion. :)

You do not have to pay the salary, just the social insurance.