It doesn’t know how much money you have, it doesn’t measure the purchasing power of individuals. It also is based on a basket of 3000 fungible goods and services without accounting for value of quality or outcomes; as explained already in this thread.
It doesn’t take into account median income, income and wealth inequality, unemployment rates or any other factor that probably matters more than how much a bag of potatoes or a new highway costs.
Bulgaria has a worse GDP PPP per capita than Russia and many other far worse places. Guyana has a better GDP PPP per capita than France or Canada.
Greece’s GDP PPP per capita and in general is now higher than its pre-2008 crash, its nominal GDP however is still nearly half of what it was.
Youth unemployment is nearly at 40% with overall unemployment at 10-11% which is still masked by the fact that many people were still able to retire early over the past decade as they were still eligible for the 60 year retirement age (and earlier for certain occupations).
None of these factors alone can be used to extrapolate how well people are doing it take far more in-depth and even somewhat subjective analysis.
For example Norways GDP PPP per capita is about 30% higher than that of Finland however the average Norwegian is probably not better off than the average Finn especially not by “30%”.
Using GDP PPP per capita or otherwise as a rebuttal for economic stagnation due to lack of GDP growth is disingenuous at best and dangerous at worse.