iPhone XR water damage

I have a an iPhone XR in mint condition with no cracks or scratches that I took swimming no longer than 10 minutes and at most no deeper than 30 centremeters. Unfortunately shortly after it greenscreened and then shut down and have not been able to restart it since. Apple says that the phone should have been fine and I only took it under water after they said it was ok. Can this be a warranty issue? I don’t have the receipt for it anymore however

[Re-Titled by Moderator]