While I agree with many things you said: Unfortunately, any UV light exposure is causing harm not just the exposure leading to sunburn. There is no safe level of tanning.
Use the same mental model as with X-Ray exposure.
Instead, there's a dose-response curve, as with almost everything else, and some moderate level of UV exposure is almost certainly net-beneficial.
Further, getting a light natural tan from the sun itself, without ever becoming uncomfortably burned, is probably more indicative of that optimal level of UV exposure than remaining ultra-pale from absolute avoidance of all sun-UV.