I love exploring the depths with as little light as possible. When I have to I’ll use Riju’s power or brightblooms but for the most part I really like running from Lightroot to Lightroot without aid.
I’ve also discovered that if you put your map on the earth layer it will show in the mini-map and help you around obstacles.
I had no idea about the star rod! That’s great! I think the depths have opposite topography of the middle map for most areas so I’ve been using that quite a lot.
I found t very handy in the early game, but then started to begrudge using the star fragments, lol.