I like your general "cosmic ocean" approach to these questions as this concept can be found in several other creation stories.
Quote from -
Creation myth - Wikipedia - "In creation from chaos myths, initially there is nothing but a formless, shapeless expanse. In these stories the word "chaos" means "disorder", and this formless expanse, which is also sometimes called a void or an abyss, contains the material with which the created world will be made.
Chaos may be described as having the consistency of vapor or water, dimensionless, and sometimes salty or muddy".
If one knows of the Standard Cosmology way of explaining the formation of our Solar System, this mythical telling can IMO easily be compared to the ancient stories of creation in many cultures.
The standard cosmology explanation also take off with "a cosmic cloud of gas (watery elements) and dust" which comes together and create the Solar System", but when it comes to the ancient telling, the creation story includes Milky Way terms as the ancient observations "only" includes the Milky Way at the largest in their world perception.
The first creation of firm matters happens when "cosmic rivers" comes together in a swirling motion and creates "firm matters" and spheres of gas, and from the first firm matter all firm planets and stars are created in the Milky Way.
This creational/formational process explaines how the subject of "earth" in the Bible can occur before the very creation of our Solar System and the planet Earth. The first "earth" term simply explains how firm matter is created in general, whereas the second mentioning in the Bible speaks of the factual planet Earth and how it is positioned in the overall cosmic imagery/firmament.
We have several
Sea Monsters in ancient cultural mythology. Once again, if we connect these sea monsters to the mythical concept of the "cosmic ocean" and other celestial "water issues", we can find several links to cultural mythological stories.
For instants: In Norse Mythology we have the "Midgaard Serpent", Jörmungandr, which encircle the entire Midgaard, the home of humans = the Earth. The only celestial structure which encircle the Earth is observed as the white Milky Way band which is observable in the night sky all around the Earth.
So, the Milky Way contours are connected to several mythological symbols, but in the case of the "Milky Way River", a Sea Serpent is also connected to the cultural stories of the Milky Way. Other Milky Way symbols are specifically cows, which logically connects to the white color of the Milky Way, and it is the same case of a Mother Goddess who also is connected to the Milky Way via her breast feeding milk as described here at -
Cattle in religion and mythology - Wikipedia
These sentences contains both celestial and terrestrial terms, which automatically cannot be connected and described logically as a whole.