The other way was working as Blockchain developer on some sector like Oil, Market, Food, etc and also being a lawyer or even marketing on some blockchain-based company
This is not easy to achieve as you need some extensive knowledge about blockchain technology. I work in the IT industry and the qualifications required to apply to these jobs need experience of almost a senior developer. Job offers about cryptocurrency is not yet common in our country unlike in the US. If you plan to treat crypto as a full-time career, your only choice is only through trading.
Yes, it depends on the country we live in, in my country blockchain and crypto startups are very popular. So as long as you have a basic knowledge of crypto you can start your job and most companies pay in local currency, not crypto. I think we can consider crypto a full time job if you can apply like the companies I mentioned. For investing or being a day trader there is a lot of risk and we should just treat it as a part time job in our spare time because they don't always guarantee our income.