The first line of defense appears to be not skincare but diet! I’d never heard of this until a few years ago, but somehow omega 3 oils and other fishy ingredients help protect skin from burning. Olive oil contains omega 3 fatty acids, too. Some seeds and nuts (like walnuts) contain omegas, too.
Shade is good of course. Or if there is no shade, we go all Georges Seurat and use umbrellas. I feel I should don a long dress with that umbrella, and actually I would if I still had one. I like to feel like “Elizabeth Bennet” walking through the grass. LOL
We also use long sleeves, long pants, hats, and “bandanas” (AKA random long pieces of fabric leftover from sewing).
If you wear glasses or sunglasses, you can cut a piece of leaf (Romaine or something else out of the kitchen if you are like us and have no deciduous trees!) and put it under your glasses over your nose! (But I also recommend–for health–take those glasses off for just 2 minutes a day to let the sun help you. This apparently cleans the blood.)
They say in old times people put leaves under their hats, too, though this is for cooling more than sun protection. Might be nice, though, if you are bald and your hat does not have an SPF rating (tightly woven).
Literally today I just found out they also make full coverage swimsuits, which are so cool!! Note: I have not tried these myself and don’t know the “extent” of sun protection, but it looks like a very reasonable option to me.
Black Hills Picture Books Edgemont, SD 57735