Is Hunter’s March really optional?

I’ve received the wanderers crest, as well as the silk spool, and met the forge daughter. I’ve been around the map a few times in Bone Bottom, the Marrow, and Deep Docks, and I can’t find any additional entrances to other areas. I’ve gone through the Wyrm Ways but I think I’m stuck due to just having dash.

I saw somewhere that Hunters March is optional, until a later part of the game. Is there a particular area I should be focusing on to progress? I’m trying to avoid most spoilers but if I need one to progress I’m not pressed.