I need help without spoilers please

So I just "finished" the game with the >! Verso ending !<, and I can very much tell that this is just one of the endings, there are much more than >! Verso and Maelle !<, however I'm not sure. I'm sure we can fight Clea as well, and there is a mention of a Simon in the journal.

Plus, there are mechanics that I never unlocked, like diving with Esquie, there has to me more to the story.

Or maybe everything else is optional and I actually finished it ?