let him make his fortune here in Poland and invest there.
Nope. That doesn't work. You conveniently overlook entrenched and widespread corruption in Nigeria. You also don't care at all about Poland and so naturally believe money earned in Poland should be syphoned off rather than reinvested.
In fact, your lame idea of Africans migrating to Poland and then investing their earnings back in Africa has already been tried and ended with unsurprising failure and criminality.
Take for example your homophobic migrant upstart showman John Godson whom you idolize:
Ex Lawmaker Raises Alarm After Nigerian Man Flees With His Building Funds.John Godson, has raised an alarm and...urged fellow Nigerians to help in finding...Godswill Kanu of...Abia State. According to the ex-lawmaker who is also from Abia state...Godswill Kanu...was his construction manager before running away with funds entrusted to his care.
Source: nationalhelm.co/2016/12/ex-polish-lawmaker-raises-alarm-after.html
Had Godson managed the money himself on the ground back in his homeland then he wouldn't have had this problem. It's called proprietorship and would be fully in line with your Randian value of individualism.
Instead, the third world opportunist preferred to stay nice and comfortable in the society which Poles did all the hard work and struggled and sacrificed to build.