The Flamechase Journey isn't just a mission to save the world from a literal encroaching darkness. There has been a masterfully interwoven thread about the encroaching darkness being the stagnancy and clinging of those like the Okhema council or the Janusopolis head priests or the king and captains of Castrum Kremnos who would rather continue to exploit and claw at whatever little comforts they can at the expense of the lives of the people their positions would otherwise tell you it is their sworn duty to protect, serve, or offer the truth.
It begs the question, what, even at the literal end of the world with destruction and decay and a malignant mutation closing in, the counsel thinks it can gain? Petty, short-term power? Mydeimos would have us believe that Aglaea rules by charisma and force of personality, while Anaxagoras would have you consider that in fact she has a passive but very pervasive control of everything and everyone in the city, which at least is something he considers uncomfortable and disagrees with.
As someone who values free will and the value of individual life, being party to the Flamechase Journey, which is in-text stated to be uncaring of life, to be something that churns Chrysos Heirs over the course of 1000 years in its grindstone... well it is not that either Mydei or Anaxa are wrong. The 3.2 update will likely provide more context about who the developers would have us believe, but Hoyo has been remarkably good so far at allowing two ideas to sit in tension. Hopefully, that will continue, but even if not, narratively there is evidence that both men are correct (and it's notable Anaxa is said to vote against the Flamchase, not with the council).
Ultimately, there is a part of Aglaea that does what she has to out of a dark necessity, and we are on her side against the Council whatever the feelings about the Flamechase Journey. It's a sickeningly realistic exhibition of very real human behaviors in the face of uncertainty.
When the Chrysos heirs return Oronyx's coreflame, there is a civilian speaking in the background saying that the "chrysos heirs don't care about safety, only want to cause chaos". As players, we are not supposed to believe this assessment, but it shows us the opinion of what is likely to show up as a vocal portion of the population. Even if it is minority of Okhema citizens who truly hold the believe that the Chrysos Heirs are part of a selfish and pointless quest, if they are loud enough, it won't matter that it's a minority, plenty of people will join with a mob mentality. This individual is himself parroting something that was said to him by a Council member or someone relaying their words, but is really using this statement to exhibit a different and understandable sentiment - that due to witnessing the process of the Flamechse, he himself no longer feels safe.
The Council is selling a false but potent vision of safety - that Okhema was in equilibrium before the Chrysos Heirs began making visible progress on the quest which is true, that the Black Tide is advancing due to failure of the quest, also technically true, and that the Chrysos Heirs cannot actually guarantee every stone of Okhema remane safe, also true.
Humans as a collective don't tend to deal with instability well, which enables these hard truths to be peddled by the Council in a way that allows denial to lead to anger that the peaceful lie was not preserved for longer, that allows the Council to lie to the people and effectively say that if we do not deal with this problem in the only way currently known that allows humanity as a whole to win, it will allow some to live in comfort and peace for a little bit longer, which for a lot of people is plenty.
The High Priests of Janusopolis would have rather sold lies and false prophecies than dare to make the populace uncomfortable by indicating disaster could be on the horizon, all to preserve a power that would not matter any longer once the city fell and a majority of its inhabitants were dead. All to preserve a comfort, that would not be enjoyed by the majority of its people.
The King of Castrum Kremnos would have rather sacrificed hundreds of his own people of extended periods of time and tossed his own child off a cliff than face the fact that endless warfare at some point becomes cheap and pointless, death before glory indeed.
In my opinion, the narrative is framed to show the current and historical "leaders" of the Amphoreus city-states as seeking their own prestige, power over others, and ability to bully and control, over power with the people they are supposed to serve and guide.
The interesting thing is that Tribbios, who has devoted her entire life to this prophecy which she believes to be meaningful, also needs the prophecy to be meaningful (ie prophecies have as much weight as you give them) because she sees it specifically as a way to reach her vision of belonging, acceptance, love and freedom.
She speaks of "everyone" actually wanting the prophecy to succeed in their heart. In some way, this is likely true. Most people want the Black Tide to recede, and Amphoreus to flourish once again (...except those who already "flourish" because they benefit from the fear and chaos created by the Black Tide, as it means people who are not interested or necessitated into being leaders look to those who purport to be able to provide something stable in unstable times). However, the language of speaking for everyone also speaks to the Chrysos Heirs sharing some of the fatal flaws found in those of the Council, or the High Priests of old Janusopolis.
There is a memoria fragment which provides a warning which, as many of the fragments do, provides relevant background that adds depth to the narrative. "Do not give people false hope under the guise of prophecy...?" Given to one of those Janusopolis priests who "manipulate" prophecies for their own gains, this is both an example of the lengths that these leaders would go to preserve their power and keep people burying their heads, loudly declaring that everything must be fine because a prophecy said so.
It may also be a warning to us, that although this holy maiden did not have the skill, perhaps another one does.
The only difference is the intention behind the Flamechase and the Council members, who are shaping up to be part of the 3.2 antagonist forces. While Tribios' desire to fulfill the quest may be selfish in some way, I think she does have a genuine desire to give everyone in Amphoreus the possibility of pursuing something equivalent to the happiness and companionship that she longs for, which cannot happen with the Black Tide bearing down and threatening to corrupt everyone.
The Council (and other past leaders in Amphoreus) aren't wrong to question the prophecy or even allow space for legitimate concerns of citizens who do not have a clear idea of what would come instead of their everyday lives in their homelands. This fact is narratively reflected by one of the Chrysos Heirs themselves questioning the purpose of the Flamechase Journey. However, we see them essentially turning legitimate concerns into a weapon to sow fear and inaction amongst the populace. Anger at least, can feel like doing something when it feels like current action is not resolving important social issues (here THE most important that lands outside Okhema are literally being eaten up and monsters which can also eat you are similarly encroaching).
Essentially this long post is a meander through some key points from the latter half of chapter 3.1, and praise for creating a tightly woven microcosm of very real issues that arise from the necessity of a ruling body for large social groups. It is a skill to allows trait that are similar between our erstwhile heroes and villains to reflect and magnify off one another. Incidentally, this is something seen not just in much good storytelling with such dynamics, but in actual greek plays as members of the Chorus will step out to speak for groups of non-protagonist characters throughout the narrative. All in all, it's a well done examination of what powerful people might do (even if it looks bonkers ridiculous to an outsider, like truly what does that assasine-ing council-woman think is a reasonable alternative to fighting the Black Tide when everyone is running out of time? She immediately gave the energy of being upset the Flamechase was not her idea, which is and almost comical level of self absorption) but also what people who have come into power (like Tribbie) might start to do in order to make sure their long series of action have some meaningful consequence, which is sure to be another through-line as we start to investigate more into the Flame-Reaver's origins.