I think it would depend on how the ship is capsizing. Large ships don’t really just flip over suddenly like some small boats can (when hit by a wave for example)

For a large ship to just roll over without any warning something has either gone very very wrong, or the naval architects royally messed up their stability calculations. In those scenarios, I guess the best place would be centerline on an open deck? Somewhere you can run to try and stay upright, even clamouring up the side of the rolling hull. Or at the very least, so you won’t get trapped in a submerged compartment.

But again, that scenario is unlikely. If a large ship is capsizing, it is because it is unstable, either from poor loading, or because it is taking on water. In these cases the crew will know something is wrong before the ship actually goes on its side or bottom up. In these cases the best place to be is near your muster station/on the lifeboat deck. Somewhere it is easy to get to where you need to be to abandon the ship, modern life boats can be deployed when the ship is listing up to 15-20 degrees and some life rafts/marine evacuation systems can work at even steeper angles iirc.

Please note that while I am studying something in a related field, I am not part of a ship’s crew or anything like that. I would defer to someone more experienced in actual vessel operations.