Personally my rule of thumb is:
Be active in the sun.
It’s okay to get some sun but just baking under it for hours isn’t great. Shirt off for a run? Great. Swimming for an hour? Great.
Be active, get some sun
That very much depends on your climate and skin type. In many circumstances, that kind of casual exposure can still result in dangerous levels of UV exposure.
If you maintain a base tan (equivalent to 2 hours in the sun or 10 minutes in a "standard" tanning bed, per week), the melanin is highly photoprotective for any additional UV exposure.
Tell me you don't live in Australia without telling me.
Doing that in Australia is basically the fast-track path to skin cancer thanks to the hole in the ozone layer.
Going back after ~10 years away I was staggered to experience the feeling of hot chilli peppers being ground into my skin after standing in the sun for ~5 minutes.
Nowhere in Africa was like that.
https://www.abc.net.au/news/2024-02-13/sun-safety-position-s...
There's something about exercising outdoors that is incredibly effective at lifting my mood, well beyond the effect of doing the same indoors. For that reason you will find me outside all year round regardless of the weather.