Will my iPhone 15 Plus still be water-resistant after repair?
Will my iPhone 15 Plus still be water-resistant after getting the battery replaced by Apple due to swollen battery?
iPhone X, iOS 16
Question marked as
It will have the same IP rating for "water resistance" as when new.
However...
Best advice, dont get them wet and never immerse. The ratings are theoretical and not guaranteed if they do leak. The basis on these claims is that you must have abused it. I've been there.