Piz Buin one day long gets my vote.
Stick it on half hour before you leave the house, it’s not sticky after that half hour and you can’t rub it off. Fully waterproof and sweat proof and lasts up to 8 hours.
I used factor 15 in Mozambique last year, after 2 weeks in the blazing sun (including swimming in the sea without need for reapplication) absolutely no burn in over 40 degree heat (I can go pink even in the british “summer” at times) Last but one day wanted a tan, didn’t put it on as thought i hadnt burnt yet, the sun must not be too strong here – within half an hour burnt to a crisp, even a lobster looked pale next to me!
Silly lesson learnt and a very big positive vote for Piz Buin one day long