As someone who believed the marketing hype for the iPhone 11 and took it in the sea, my subsequent visit to the Apple shop to get a replacement was illuminating. I explained I’d only been in the surf, the phone spent maybe a minute actually under water and the rest of the time it just got splashed. Apple guy checked the sensor, it indicated water damage and that’s all that matters. I tried arguing about their adverts of the time but I couldn’t prove what I said happened. I was glad of my apple care as it only cost me £79 for a full replacement. He said it’s always best to assume your phone isn’t water resistant and if it accidentally gets wet it might survive rather than assuming you have a fully waterproof device. I know that the 15 is supposed to be ‘better’ but I don’t take mine in water without additional protection.