The Vishaps such as the primo geo vishap, and the bathysmal vishaps are followers of the Seven Sovereigns, a race of dragons that were the original rulers of Teyvat before the First Descender came. This should ring a bell since the idea of the descenders was introduced in the Archon quest in Sumeru.

The Bathysmal vishaps in particular should be the vishaps that had had been existed in Enkanomiya, hiding in the vishap realm.

Generally, the lore and symbolism of the different bosses are buried beneath text of different items and artifacts, not just quests. Even if they don’t necessarily connect to the story, they function to expand the world building of Teyvat.