Avoidance of excessive sun exposure is the solution. Harder if you live an outdoor life outside of work. You're exposed to.It all day. I slather early doses of an all day factor 30 minimum before going out or on going out if camping. Rieter p20 is my favourite. Then boots factor 30 with 5 stars protection for the other uv type used throughout the day. All day sun screen doesn't really exist.
The other thing I think helps me is to get exposure to sun early in the year. The sun is low in the sky and IME is less likely to burn. For me it slowly tans, which gives me a certain amount of protection.
Ultimately I'm fortunate being the sort who rarely burns, tans and generally go a rather nice colour tan. I was out in the height of the sun at the weekend for about 3+ hours without cover or sun protection. I burnt red a little but it was only sore if i scratched my skin where it burnt. I only.burnt on the back of my upper right arm just above the elbow below the t-shirt.
Last time I burnt properly I was a young child. Blistered all over my shoulders and back. Skin peeled off a day or so later. Blistered skin had pus in the small blisters that burst when I rubbed them. Within the, week I'd recovered and had turned very tanned.
My advice is find your own protection levels. Someone I knew needed rieter p20 highest spf they do applied a couple of times hour before going out. Then factor 50 half hour before going out. Then regular re-application of spf 50 hourly. Plus covering up as much as possible. Otherwise she went straight from so white she's translucent to blistered in less than an hour.
There was a joke I heard, tasteless but the original was funny, about scottish people tanning by turning white.