Exactly, a Northern European adapting to sun exposure doesn’t mean getting a tan, it would mean evolutionary pressure to adapt to, say, sunnier California via n

Exactly, a Northern European adapting to sun exposure doesn’t mean getting a tan, it would mean evolutionary pressure to adapt to, say, sunnier California via natural selection over a few thousand years where less sun fit portions die off earlier, while the surviving group slowly gets darker over many many generations or better at repairing damage. If you’re fair skinned but find yourself outside the low UV region that your skin is adapted to, you are welcome to begin the new adaptation by avoiding sun protection and going outside without regard to the UV index. I, however, will not join that genetic adaptation.