I would have no hesitation whatsoever in doing what you describe. I'd also be comfortable flying six feet above the lake en route to the location from which you want to shoot the photo.
Just don't rely solely on the altitude indicated on the...
I’ve flown a drone above water since I bought a Mavic Pro when they first came out. Sea, sea loch, loch, lake, river and stream. Still got the Mavic Pro which has never needed any repair other than propeller blades which are disposable parts...
Why can’t you start from the hovering position, then climb to get the shot you want to make, then reverse it in post. It means that you’ll be concentrating on getting the low point correct without being distracted by getting the shot.