Hey kidz!
What's G'raha's character? He's a WoL simp! Let's make a storyline where he gets challenged and has to face his own hidden flaws - Alexandria storyline!
In Alexandria, the northernmost city of the continent of Meracydia, the Time Mages have installed a giant time nexus where the future timeline of G'raha's and our timeline are held in an infinite time matrix. Why? Because they have an ideology that states that the demise of the 8th Calamity timeline is bringing salvation to the other timeline, like a Yin Yang thing. This is obviously bs, but they have good arguments: Everything in our timeline gets good, the thousand year war of Ishgard has been solved, Garlemald the needlessly expansionist empire is gone now, the Ascians are now gone and can't do evil anymore, the tribes are becoming accepted, the world is growing together, even the First has been brought back from the brink of destruction. Since this all coincides with the time around the creation of the time fork and since the alt-timeline is slowly dying they believe things naturally balance out.
So essentially the demise of G'raha's timeline is justified because it makes our timeline cool. So when G'raha steps up to defend the WoL he gets accused of being a hypocrite, since he was ok with the WoL not saving the past when they traveled to Elpis, while he himself traveled back to actively alter the timeline to save it. G'raha defends the WoL because the world had to be sundered for them to be able to travel back and save their world. However they show him an alternative that could have been achieved for the 8UC timeline: it could have been saved as well, a small enclave of people would have survived and slowly repopulated and rebuilt the world over thousands of years - that was the original plan of the Ascians - however since all resources were dropped to build a time machine, this was no longer possible. G'raha gets accused of giving up hope and abandoning his broken people, which he has no answer to. They say it was the idea of the Warrior of Light that blinded him and he didn't actually believe that a world without them was possible. Thus he built a mental image of the WoL as a savior-figure, essentially a god without whom the world could not be saved.
This is why they say that in Alexandria everyone is a Warrior of Light. However they actually made use of G'raha and the 8UC team of mechs in order to split up the timeline, so even while flawed people can contribute and they think it's for the better anyway so they thank G'raha but he doesn't like it. As a little side quirk there is a previously unemployed sundered Ascian originally from the 8UC who now also works for the time mages. They actually handed over information to the timelords in order to prove their loyalty, because they got contacted by Emet-Selch while we were light-overloaded in ShB - Emet gave them some info about time travel he got from G'raha, which G'raha doesn't remember snitching, but Emet aether-absorbed some of the exarch's jumbled memory while torturing him or whatever he did. So that sundered Ascian, let's make her a girl for a change, deciphered the memory and turned it in after the fall of the ascians to help the time mages - they didn't actually know how time travel works. It was the 8UC guys who came up with it, the time mages were created as a result of G'raha traveling back, which allowed them to create a time bubble in which they essentially stomped Alexandria out of the ground in the image of ancient Alexandria which was destroyed by the Allagans. They built a time nexus but are only watching over the timelines and keeping them seperate, not altering them any further, which they are forbidden from. In fact if they want to cross timelines without authorization they get instakilled.
Anyway, so G'raha now has to realize that the Warrior of Light wasn't actually the means of saving everyone, which he takes like a champ. He admits that it was his idea of us and not actually us and that the idea helped him, but that rather than take us as an example he made himself small in his mind and thought he could never do what we did. He faults himself for it but doesn't linger on it or get depressed, cause everything else was real. He's still our friend and still loves us and so we go on an adventure together where he can prove himself as a force of nature or something and he treats us less like his idol and more like someone equal.
Anyway if you ask "well what happens now that we know that the 8UC could have been saved?" well G'raha also continues to ask himself that but I wouldn't make that a major story beat involving time travel and shiet - I mean there's nothing he can do about it now either. It would just be lore that ties to G'raha's past and I liked the idea of a city of time mages and to name it Alexandria because of the primal Alexander (like in FF9) , but we had enough time travel and ascian ties in the story for the time being and it would just be a place in the world that does it's thing and can stand there and just be potential for a new (possibly side) storyline somewhere down the road. The main story should focus on something totally new that would for sure involve Alexandria as a city with real people, where the time mages would of course be a force but tied to something current and new with the stuff I described here just being some neat background lore.