I found out where to go next!
And more importantly, I also couldn’t resist back tracking and back to the dark area. I figured if there’s a dash ability to procure there, then it’s worth fumbling around in the dark.
And it was! Once you explore it a little in the dark, you do find a little ball of light that helps you see. And once you get the Dash ability, the whole area lights up (thank god). It’s actually a really great area. Highly recommended. Now, as to when you should be able to tackle this area? I have no idea. I had a relatively easy time since I have quite a few abilities in my repertoire. I imagine this area would be a lot harder for people who tackle it near the beginning of the game.