iphone flashing apple logo then completely dead

i have an iphone 11 pro that should be completely waterproof.

After using it to film in shallow water yesterday it worked fine for around 20 minutes then i noticed that the video app was open and it was very hot so i powered it off.

After around 5 minutes i tried to power it on but all it was doing was flashing the apple logo. It was also very hot around the camera.

i cooled it down by a air con and it then showed the logo that it was out of charge.

when i got back i tried to charge it however it showed it was charging then went completely dead. it has only been a black screen ever since.

i will note that it has no cracks or damage.

Also, where i was the weather was around 32 degrees.

I have also already tried to restart it by pressing the volume buttons and then the power button as that all i could find to do.