Best country to immigrate as 21 years old?

The best country is a join over many things:

The one you and your family (if they're making financial sacrifices) can afford.

The one which will offer you pathways to citizenship and family migration in the future.

The safest one.

The one you have a support community in our nearby.

The one with good primary health care.

The one which recognises your existing tertiary education investment.

The one with a climate you can handle.

The one with food culture you can handle.

It's multivariate. You've got a lot of research to do and you didn't make enough of the input conditions clear.

Sometimes a stepping stone move is needed.

Sometimes you need to "try before you buy" with a student or young person working visa.

Don't undervalue the less developed countries. Your cost of living may be lower than the property taxes + utilities on a similar house in a developed country.

Consider building sites, apps or other forms of recurring revenue. If you have the tech basics, your next step might be exploring sales.

Just move to the best place in your country, learn coding and sell your services online. Move later - it is difficult and costly. You will need to write a lot more about yourself if you want people to interact. If you do a project and show people then you might get somewhere.

Canada