Multiple videos of that sort of thing happening came out. Tesla driving threw high water. Musk commented something that for a short period they could float but in general they said this wasn't a supported features and don't do it.
Then for the Cybertruck Musk said it should actually be able to float. But it was said as 'we are shorting for this' not 'this is a feature count on this'. As it stands this would void warranty.
Tesla certainty not ever suggested that they could turn into boats in emergency situations.