You have done a detailed and well-researched fact-check on the idea that drinking too much water might be detrimental. I like how you pointed out that dehydration can cause headaches, nausea, cramping in the muscles, and fogging of the brain. It's very clear how drinking too much water can overwhelm renal function and throw off salt balance, as you said.
But I saw that you might make your case stronger by mentioning more precise medical words and conditions—like hyponatremia—that are linked to dehydration. Confusion, convulsions, and even coma are signs of hyponatremia, which WebMD defines as when blood sodium levels fall too low as a result of consuming too much water. Overhydration can also result in brain enlargement, which in extreme circumstances can be fatal, according to Healthline.
Adding these extra facts and medical jargon might provide readers a more thorough grasp of the dangers of excessive water consumption, even though your fact-check is sound overall.