The papers claiming Spinosaurus was a diver or a strong swimmer rest on very weak evidence at best.

So Spinosaurus is a super weird and exaggerated version of what was already a kind of super weird group of theropods. So Spinosaurus is properly strange. And then, as you kind of hinted at, super controversial as well, because various papers have claimed it's a diver or a really good swimmer, and I think the evidence for that is very weak at best.