The op didn't say Nigeria is better than Canada.
She listed points, and I can boldly tell you that all she said are true.
After Moscow, Russia, Canada is one of the coldest countries on earth, so it is normal for blacks to feel awkward about the new cold weather, and that could have made many people leave Canada, so the op didn't lie.
Wealth creation: the op is 100% correct. It is easier to become rich in the USA, Australia, and other developed countries than in Canada. To become rich in Canada is very difficult, just as it is also difficult to become rich in the UK as a Nigerian migrant unless you join a business/entrepreneurship.
Go to any community in Nigeria; the wealthiest people (professionals) living abroad from that community are those living in the US, Europe, and maybe the UK. You can hardly hear of a wealthy Nigerian living in Canada, so it is proof that Nigerians living in Canada hardly become rich in Canada. They could be comfortable but rich, nope.
The op is correct with that point.
Loneliness: the op is also very correct.
Medical professionals: Canada is the only country that requires a foreign-trained Nurse to acquire a Canadian nursing license before studying nursing in Canada. It is bullshiiit. The Canadian healthcare system is below the US, UK, Germany, and others that accept our Nurses without further educational qualifications from their country. How much groundbreaking medical research comes out of Canada? None. How many new drugs are manufactured in Canada? None How many rare case surgeries are first discovered or performed in Canada? None
Canada is good for Nigerians tired of Nigeria. It has no other developed country option to migrate to, but it is never an option for someone that can migrate to the US, Australia, Germany, etc., to consider.
The US is the number one country where nobody can become a billionaire.
Ellon Musk tried in Canada and couldn't achieve his dream of becoming a billionaire in Canada, so he migrated to the US, and today he is the wealthiest man on earth.
How many world billionaires come from Canada? None known but the US, UK, Australia, Germany, France, etc. have a long list of billionaires which should tell you where the wealth is.
Canada is not for anybody that desires to become wealthy; it is for people that want to break the yoke of family poverty and give their children a secure future to become middle-class and upper-middle class.