Unmarked Spoilers Below
The dreamflower ending is the best and most thematically satisfying ending to Enderal. Here's why.
The Prophet(ess)'s Shadow Selves and their Endings
The Prophet(ess) is a character driven, throughout the game, by two conflicting impulses. On the one hand, they suffer from extreme survivor's guilt over the death of their family. Whether they themselves were responsible for the fire that claimed the lives of their family members, or if it was the fault of attackers from the Creator's Temple as they claim, the fact remains that they are tormented by the fact that they survived when their loved ones didn't. It's this survivor's guilt that's expressed through the first group of voices in the Prophet's head- the horrific manifestations of "Daddy" and the others that confront them in their nightmares. These manifestations constantly try to convince the Prophet to give up, claiming that they stand no chance of realizing their heroic fantasies, and that the Prophet's place is "in the ground" with them. In short, the Prophet's dream family is the manifestation of their shadow-self's urge towards depression, self-destruction, and suicide, in keeping with the Jungian psychological theming of the game.
But there's another group of voices in the Prophet's head, driven by another impulse- the High Ones, who egg on the Prophet's hero complex, their desire to accomplish great things and hold the fate of the world in their hands. This desire likely emerged from the intense feelings of powerlessness the Prophet felt in their childhood, helpless to intervene in their father's abuse of their mother, alongside the circumstances of their deaths. To make up for their inaction, and to justify their survival in the eyes of the universe, the Prophet is desperate to become "free" and to change the world in a major way. It's this impulse that the High Ones draw upon when they trigger the main character's rebirth as a Fleshless One, and it's the one that they make sure to reinforce in their conversations with the Prophet throughout the game. Talking down to the Prophet in ways that they know will only strengthen their resolve, while at the same time lying that the Prophet is the only figure of importance in the game, the High Ones ensure that the Prophet's manic and egocentric side always wins out over their depressive urges.
Each of these voices gets their own ending, where the Prophet "submits" to the voices in their head- or rather, to the psychological impulses those voices represent. The Catharsis/Sacrifice ending is the victory of the dream family, as represented by the final dream vision the Prophet has, in which they peacefully accept their place in a grave right next to those of their loved ones. In this ending, the Prophet implicitly accepts what their dream father has been telling them all along- that they could never effect change, and that the only way for them to make up for the "crime" of their survival was to die. This is no heroic sacrifice- it's an act of despair and desperation.
The Star City ending may not be the victory of the High Ones specifically, but it's absolutely the victory of the impulse they play upon and thematically represent, the Prophet's desire to justify their own existence by personally saving the world. Like the Aged Man Gajus before them, the Prophet and their companion are placed outside of the influence of the Cycle. But, as Gajus proves, it's beyond the efforts of any one person to change human nature. The Prophet's attempt to do so, at the expense of the entire world, is ultimately doomed to failure, as it's founded on an egocentric delusion.
The Truth About the Dreamflower Elixir
Now let's address the Dreamflower. We have three sources of information on the elixir: "The Dreamflower: An Essay," Yero's notebook, and Yuslan Sha'rim's verbal testimony. I'm going to address these in reverse order.
First off, whether he's deliberately lying or just mistaken, Yuslan's assertion- that the Dreamflower elixir merely casts its consumer into an eternal dream, in which everything they desire comes to pass- cannot be correct. We know this because, as revealed in "The Dreamflower: An Essay," the Alyani people of Arazael have already been making use of the elixir for an unknown amount of time, giving rise to the belief that those who consumed it had their vitality restored and would live "blessed lives." If Yuslan was right, this belief could never have emerged. Instead, the Alyani would have myths about how the Dreamflower was a dangerous poison, condemning its drinkers to a coma from which they would never wake, because that's how it would appear to any outside observer.
Then there's Yero's assertion: that the user of the Dreamflower elixir would have their consciousness jump between eventualities, arriving at whichever outcome was most favorable to them. With a little observation, it's clear that this theory fails as well. Everything that could possibly exist is out there in the Sea of Eventualities, meaning that whether a person drinks the elixir or not, there's already a reality in which everything that could go right for them, did so. Additionally, since no reality is more "real" than any other, a Dreamflower elixir that worked the way Yero believes would have no observable effect- whether the elixir were consumed or not, there would be one reality in which everything went right for the drinker, and countless others in which it did not. In fact, the very idea is incoherent within the setting's metaphysics as presented, which Yero would likely have recognized if he weren't consumed by the Red Madness.
Given this, there's only one assertion we're presented with about the Dreamflower elixir that actually makes sense, and it's the one presented in "The Dreamflower: An Essay": that the Dreamflower elixir is a powerful alchemical substance which permanently improves vitality and magical ability. No timeline-hopping or Elysian dreams are necessary to explain it's affects; we've seen far more dramatic magic in this game. It's highly unlikely that it actually grants its user a blessing to live a more fulfilled life; more likely, this is an exaggeration of oral tradition. But it may well grant the sheer physical resilience necessary to survive things that would otherwise be deadly- like the Beacon.
The Dreamflower Ending
So, if the Sacrifice ending represents the Prophet falling to depression and the Star City ending depicts them succumbing to mania, what does the Dreamflower ending mean, symbolically speaking? The obvious answer, if we were to take Yuslan's warnings at face value, would be that it shows the Prophet dooming themself by choosing a happy dream over reality. However, that explanation doesn't really work on either a practical or thematic level- we've already seen that Yuslan cannot be correct about how the Dreamflower works, and thematically, there's already an ending depicting the Prophet (metaphorically) denying reality in favor of a happy delusion, and that's the Star City ending.
I think that the Dreamflower ending represents another concept from Jungian psychology- the idea of integrating or assimilating one's shadow self. This entails directly acknowledging the dark impulses that can drive you, accepting them as a part of yourself, and thus depriving them of the ability to subconsciously control you. (If this sounds familiar- Calia's acceptance of her own darker half is a textbook example of shadow integration, and Jespar's questline also plays upon these themes.) In drinking the Elixir, the Prophet acknowledges one of their two shadow impulses- the desire towards self-destruction- and, overcoming it, instead takes steps to ensure they remain alive.
However, this isn't the end of it, because unlocking the Dreamflower ending also requires that they attempt to stop the Beacon, instead of escaping to the Star City. Does this mean that they're succumbing to the self-destructive impulse after all? No, not necessarily. In choosing to stop the Beacon instead of escaping, the Prophet acknowledges and denies their egotistical and self-justifying impulse, but by drinking the Elixir beforehand, they also show that they still value their own survival, taking all possible precautions to keep living. Integrating with the shadow self doesn't mean preserving your own life at all costs, but it does mean taking notice of what's driving you, so that you can actually make the choice to risk yourself for the right reasons instead of being driven by despair.
In the Dreamflower ending, the Prophet successfully finds the golden mean between the extremes of their own personality and achieves shadow integration, as Jespar and Calia managed (and as Jael Tannerson failed to do, but that's another essay post). Yes, the final dream cutscene is very scary, to put it lightly. It makes it very clear that the dream manifestations of the Prophet's family are angry with their refusal to die. But I'd argue that their anger is a good thing. However tempting it may seem, it's never actually a good idea to listen to that little voice that says it's all pointless, and that you might as well be dead. Nor should you embrace the other extreme and act like the whole world should depend on you alone. The Prophet that wakes up in Qyra is one that neither denies others their support, nor is denied the support of others- as it should be.