Well considering the main creation story in other nearby cultures at the time also say the world was originally all water, I’d imagine it isn’t so much symbolism as it is the fact that water falls from the sky occasionally and typically looks blue.

The Enūma Eliš mentions that originally there was just water. Much like the creation story in Genesis the gods eventually separate the waters and expose land. Also curiously, the story is recorded across seven tablets and has a few more similarities with Genesis and other aspects of Judaism like man being a fallen creature (though due to man being made from the corpse of an evil god or because the gods were worried, not due to women lol)

Also, the oldest creation story I’m aware of is The Sumerian Creation Myth which also references the “cosmic freshwater ocean” and says man lives in the lower region of this ocean. The noise of humanity annoys the main god so he sends the flood from the upper ocean. But one god warns a man of this so the man builds a boat and fills it with animals. Remind you of any bible story?

Point is that even the Torah is a likely derivative work combining more ancient myths from other cultures. Because the original cultures reference the waters more as an actual physical ocean in a non-symbolic way, Id say the Bible story was meant to be literal. Almost all symbolism derived from the stories therein is likely interpretation only.

I suppose the Hebrew scholars collecting these stories could have viewed them in a more symbolic way, but the first text I referenced is a few years younger than the Torah and still references oceans in a more physical way. So, I’d imagine their meanings were initially similar.