It is a verifiable fact that sun exposure stimulates human hormone production positively. So without sunlight exposure the body is operating with sub-optimal hormone levels.
I think human migration without a doubt selected (out of necessity) for intelligence and fortitude and certain types of durability but if you look at typical UK or Caucasian physiques globally they are objectively (on average) worse than that of equatorial or equatorial-adjacent humans. This has a lot to do with hormonal dysfunction 1/2 of the year due to lack of sun, compounding (imo).
“Flu season” and significant seasonal weight gain are both phenomena that have a lot to do with lack of UV exposure / hormonal deficiencies as well.
In the same vein, the northern latitude has an epidemic of SAD that shows up every October - March as soon as consistent sun disappears.
There is also a very good large longitudinal study that found significant positive correlation between sun exposure and increased mortality. Or lack of sun exposure and increased risk of mortality - however you want to look at it.
There is solid evidence that UV / sun exposure is a vital component to optimal human health. It doesn’t mean we can’t survive without it, obviously humans can. But I would argue the credible evidence shows humans function sub-optimally sans UV / sunlight