Please correct me if wrong but this has almost nothing to do with broad human dehydration or hydration.

I think it is an interesting finding and it would be interesting to hear more about the implications from someone in the field.

I only broadly understand this is some kind of peeking behind the curtain of some process that was not fully understood before

"Dehydration" in this article is the chemical process of separating magnesium atoms from water molecules. It is not about drinking enough water.

Most of the comments here are based on the title alone. Like always.

You are correct, title is wrong. Blame this communicator. It feels that the person that wrote the text lacks understanding of chemistry or oversimplified too much. More appropriate term for removal of water around an ion is “desolvation”.