Just a quick note
I heard a story about a channel swimmer who after several hours of completing his crossing had a cold drink. His throat swelled up to such an extent that he couldn’t breathe!
Something else worth bearing in mind is the effect of long exposure to salt water in the mouth.
I was advised to swim with my mouth closed. And during my swim to gargle with a mild mouthwash .
Other things to consider.
Post swim nutrition
Recovery period. I will probably have to sleep for a week. But I suspect the thing to do is to stay active. Something to look into…