I did most of the character ending, but despite this I think these have little sense even if I can figure the cycle of loops they suggest.
For example, if each travel generates a new timeline and a duplicate of our characters, Why Izumi in Remy ending comes with us? That should generate a double of her in the next timeline too, but nowhere in most endings I saw this shows up. The idea she has killed her and the main character selves and replaced them is possible, but sincerely, is also absurd if I keep in mind that the time-travel earse most of the memories, and Izumi would end in past withuot memory of why she is here and why she should kill her clone too! Would not have sense if she would remained in the future with Remy and send only us in the past?
Also I don't understand the Adine good ending, the MC takes the role of the Administrator because Izumi dies in one of the past encounters with Reza, but actually this happens in most good and bad endings, and is the main characters that is forced or willing to go back in the past. Also Izumi was already living in the past before our characters goes in the Dragon world, and I don't find how is possible that the MC replaces her without actually kill her in past and take her place.
I think Adine ending could have been written better: Izumi is unwilling to save the human world, but I would believe if the Dragons would have forced her to change idea, or have killed her to prevent sabotage to the portal. Maverick and Adine have a debt toward you, and humans by extensions.

Or more simple: if the main character can bring objects from future, why they don't just write a note of themselves kill that Reza guy or hell happens? If you add the MC can retain some vague memories of the future events, is not far fetched they would believe of what is written there! But ok, the story would never happen in that case... :D

I think that Ipsium time-travel theory means our character has generated ten different universes that lives along, but at same time they are leaking into each other and merging into a single one that is the true ending; in theory means the bad and good ending never really happens, because their respective timelines are "dissolved" into the true ending. There is a chance that this also cause a reality meltdown, and is happens when you try to revert the death of Bryce reloading a past save (you can prevent this if you save before reload and see the "bad" branch).

However this doesn't save that the story is too confusing to follow if you don't know it already. I refer about that the game lets you choose your character to date in the order you like, but some endings are clearly meant as one of countless effort of the character to save everybody. In some ending the MC knows Izumi, but this can happens before the reader got the chance to have seen her name before like in the Remy ending. Adine and Bryce dates storyline "spoil" that the MC is a time traveller, but also the passage is clearly written in a way that presumes the player already has seen one of the other endings, instead to refer that the humanity comes from the future/alternate dimension.
I don't think this approach is justificated by the memory loss and time loops (you don't know why some finals works in that way because is one one of countless attempt). The game already let you choose in some points some phrases that fits if you already know the story or not, and I don't see why those part of the plots aren't unlocked only after you got one ending (like the MC ask Izumi her name in every ending if these are the first run). I don't see reason why don't correct some details in this way. Also, there must be a "first loop", and doesn't rule out that our playthrough is really the first.
How the plot is written is like read the chapters of a story out of order than a story we are writing with our choises. Don't take me wrong: is fine for me if there is people that liked this kind of approach; I just found confusing and limited for a game.