How to handle iPhone water damage after battery replacement?

I replaced the battery of my iPhone 12 Pro Max at an official support center two months ago. Three weeks ago, I put it in my swimming bag and found that about one tablespoon of seawater had leaked into the bag. Eventually, the iPhone stopped working and overheated even when it was off for a while. After one week, it started working again. I believe the sealing was not good enough after the battery replacement and inside of the phone should be washed. I wonder whether Apple provides any support for this kind of issue after a battery replacement.

[Re-Titled by Moderator]

Original Title: Water Leakage After Battery Replacement