I can tell you why the disparity: many Czechs who are still alive were born and raised under communism and carry all the generational trauma caused by growing up under poverty and dictatorships. As a country it wasn't really 'developed' until quite recently. And, well, old people are the most likely to die, for obvious reasons. Funny enough, Czech life expectancy at 60 is exactly 3 years less than Canada's. Meanwhile there's no way to truly measure the life expectancy of someone born today.

But if you go check metrics like doctors per capita, beds per capita, how many clinics there are, insurance coverage, etc..., it's shocking. Twice as many doctors per capita as Canada, for example.

Edit - for example, under 5 year old mortality rate for Czech Republic is 3.2 per 1000 while for Canada it's 4.9...