What it means to stand at the 'Pinnacle of Elation'
During the confrontation between Silver Wolf and Asat Pramad, he revealed that the Emanator that holds "LV999" is at the pinnacle of all of Elation, he implied that the one with LV999, or who managed to level up to LV999 among all the Emanators of Elation (ie. those who stumbled upon Aha's power fragments that THEY threw in the cosmos on a whim), is what he called the One True Player.
Back during 4.0, I said that The Elation, more specifically, Aha is special due to the fact that they ascended the Tree of Existence before ascending. I said back then that THEIR ascendance meant that THEY were able to see the entire timeline of the Universe, from its roots (the beginning) to its falling leaves (Finalities across timelines). I still think the same, but there's also one more thing. This is what granted Aha the knowledge that THEY are in the game. Ascending the Tree of Existence mean that they managed to ascend to the 4th wall, seeing everything in its true nature, a game (in the context of HSR)
So what does it mean to stand at the Pinnacle of Elation? Aha grants you the power to see the world as a game, manipulating reality through its true nature. They are indeed the One True Player as they can traverse the Universe in a perspective that gives them the most authority, a player of a game (The Universe). That's why some Masked Fools can break 4th wall, the closer you get to LV999, the more aware you become, ever more closer to the Aeon that is (that's why beyond LV999 is Aeonic Domain).
Which is kind of interesting, because the possibility of Sparkle and Sampo, and some other Masked Fools who did break 4th wall meant that they were close to the pinnacle (LV999), and are indeed Emanators. We'll see, but this is my insight for now.