Our ocean will have layers, like a cake or something. Only we know how this works with the proposed wheel world design lol.
Here's how I more or less envisioned the wheel-world thing. Honestly, I didn't describe it well the first time around.
The Hub is the centre of the wheel and probably has some significance to it be it the home of the gods/the site of the universal city/vault of dangerous things/etc. The Hub can only be accessed via the Spokes.
Landmasses are the individual planes/continents created by the gods and are inhabited by the mundane. Landmasses form a metaphysical (but not physical) circle around the Hub. Rimward Gates connect metaphysically adjacent landmasses together, allowing travel between them. These Gates could either take the form of vast oceans or arcane portal gates.
Spokes are the entranceways to the Hub. The exit points in the Hub are always in the same location and are easily recognised. Their entrances on the Landmasses are however hidden and have the tendency to shift location every now and then. Usually, it is difficult to notice when a spoke is entered. Someone walking in a forest might accidently end up on a spoke and not realise that they've walked into the Hub until they actually get there.
In between the Rim and the Hub is the Aetherial Ocean, which is the source of all water in each landmass. Hypothetically, you could travel from any landmass to another by diving through the deep waters of an individual plane and going through the Ocean, but this would be extremely difficult.