Journey doesn't just mean physically moving from one place to another, it's often used figuratively to describe moving from one step to another.
"And so our journey begins anew" implies that Midgardsormr is leading them into the 8th Astral era, not space.
This is why implicit evidence isn't really good enough by the way, not to describe something as a "known fact" anyway, because what you think the end of that story suggested and what I think it suggested could not be more different.