IMHO, it’s “fake news” that Mars ever had water.
When Curiosity landed, it headed straight away for “Yellowknife Bay” where it spent, I guess several months nosing around, but on the way over there, they took a sample from some ditch, or rut, which they happened upon, and then casually announced that they had found some sort of hydrated mineral which showed that this was a ( water ) stream bed, from a few billion years ago, of course.
Never heard much more about it, dunno.
Maybe I’m not the skeptic that you are, but one has to wonder.
( I guess you would call this “aiding and abetting” . )
Actually there is a lot of evidence that it did.