I have always washed my iPhones in the sink (careful to run water over the screen and back, but not directly into the charging ports or speakers). I have done

I have always washed my iPhones in the sink (careful to run water over the screen and back, but not directly into the charging ports or speakers). I have done this for my iPhone 6, 8 and XR over the last 5-6 years and it has never caused any damage. I used to wash the iPhone 6 in the sink nearly daily to remove the oils/sticky from the screen after eating lunch^. In my experience, you don't have to be extremely careful, you just need to be mindful that if you run the water jet continuously into a hole then it will eventually bust through... no matter what Apple marketing says. ^My workmates used to always tell me off for doing this, and I would explain that I've been doing it for years.