Each girl in each "travel" finds something impermanent that they attach to and later miss when time/location changes with the focal point of their heart already gone. Eventually they pick whether to stop the journey by picking one time/place point, or they can keep on going. They pick their desires to heal one longing at the expense of splitting. Healing one pain at the cost of another arising in its place, leaving them at the starting point. At last even their perfect place turns out to be worthless as it turns out not to be perfect either, just as dull as before. Which is even lower than the starting point. Losing everything and gaining nothing, accumulating even more sorrow.

They confront their primal submission to desires which they clearly display by uncontrollable tears and emotions whenever they don't get what they wish, or they get what they wished for but they turn out to be miscalculations leading to suffering (Desire is essentially the overarching drive behind attachment, preference, connection, love and anything of its nature. Desire leads to seeking a world in stasis of its perfect state where there is happiness and no sorrow, ease and no pain but which cannot be materialized and kept in the same state forever).

Jumps in place and time are an analogy to rebirth, each is a new start with nothing and ends as suddenly as it begins, forever, taking them into new places without having a say where to, when and why.
Them seeking answers is seeking the ultimate truth of existence that would ease their suffering.

Keith is a symbol of internal confrontation of our faulty thinking on its way to maturing into an enlightened being through the ultimate truth. Or at least he is serving them as a tool chipping off one lie after another until hopefully the picture of what existence most fundamentally is becomes clear to them and suffering stops. He appears to attempt to accelerate their detachment by continuously reminding them of consequences of actions, whether it is what they wanted, confronting hypocrisies and their actions they took in hope of reducing suffering but achieving the polar opposite each time, stacking up heavier and heavier. Keith never got problems with anything they do, he only seems to care that they attain englightenment and drop attachments (he saw mai as an obstacle to them attaining enlightenment and not from hatred).

"The One" is nameless. Perhaps a reference to Buddha as he first managed to flee the world of desires into the world of form realizing that there is nothing worth attaching to and prefering but that there only are concepts which aren't good or bad but they simply exist. Then he fled the world of form into the world of formlessness by recognizing that there are no boundaries between concepts which ultimately proves ultimate pointlessness of telling them apart and that they form one universe-wide body that through the illusion of separateness by organisms being independent fails to recognize its singularity. He achieved perfect nirvana. Formlessness not only means lack of identity in the case of her being nameless like refusing to use a name but entirely scrapping identity as a concept. She also seems to have traits of abrahamic god as she controls their next travel/rebirth and which one they now get, but she also has traits of buddha because she does not care much where they get dropped off and whether they would suffer more or not and she does not divert them from more pain. In general they made her into an image of a sage and a deity. She watches them but does not give advice. Similar to buddhas and bodhisattvas visiting realms of suffering and looking at souls in hell.

The journey never ends. Technically becauase as long as our matter exists in the universe it can rise again. Having been lying in the ground for eons to be woken up to life again one day, sentience and suffering stemming from sentience hundreds of millions of years later with no recollection of past life, no relatives, no possessions, starting from nothing, as a completely new story. "The one" did not offer to stop their journey, but to either reroll their next time or allow them to pick one from the past. In fact the journey never ends.

In the end they reunite failing to detach.
Remain in the world of desires.
Mai is right that they are not ready.
They learn nothing deep, but only learn to attach to things and let go moderately instead of climbing above attachment and desire entirely.

The point of the show is to point out the root of suffering and what it feels like, for the otaku to rethink life. But also a lot of tits are meant to keep him hooked. Very smart.

waow

>But also a lot of tits are meant to keep him hooked
well said ヽ(´ー｀)ノ

naruhodo