GDP is a very weird metric. For example, GDP includes money spent for renting an apartment, although no goods are produced in this case.

So for example, if there is a village with two people, and they rent each other's home then this village has non-zero GDP, although no goods or services are produced.

Inflated education, medical or insurance prices also inflate GDP. So a teacher in one country could produce 2x more GDP per unit time as the same teacher in another country.

Another wrong thing to do is to adjust income or GDP for food prices (purchasing power parity). This is absolutely wrong. The idea of PPP is that if in your country potato is two times cheaper then it makes you two times richer. This is wrong because a MacBook or a car are not two times cheaper. Actually they are more expensive than in the West. And if you go abroad then there will be no cheap potato either. So PPP is a total lie. It can be applied only to poorest people who spend all of their income on potato.

So if you want to adjust the income for PPP, at least use MacBook or car prices instead of potato.

I think that a fair metric would be a percentile distribution of how much money a person has left after renting the cheapest apartment and buying the cheapest food.