This got me thinking on a train of thought. In Chinese mythology Vega is a goddess of the skies / heavens who fell in love with a human, Altair.I still think Vega is the best starting point. In addition to the points in the post: https://forums.frontier.co.uk/threads/the-quest-to-find-raxxla.168253/page-1591#post-10245730,
Vega also sits directly on top of the Andomeda galaxy, when viewed from Lave. The Jewel in TDW's toast is probably from TDW viewpoint of the galaxy. That is most likely from the old worlds region.
I also found this:
"
Persian: Guardian Star
In the Zoroastrian religon, Vega was one of the four stars who protected the earth. Vanant (Conqueror) ruled the western quarter, and he guarded the gates the sun passed through each day. The others were Tishtrya/Sirius (East), Satavaesa/Antares (South), and Hapto-iriñga/Ursa Major (North)."
Source: https://earthandstarryheaven.com/2016/07/02/vega/
The Zoroastrian religon is an old Iranian religion, often considered the first Monotheis religion in the midle east. The prophet Zoroaster is the same person as Nietzsche's Zarathustra and the inspiration for this music by Straus.
Minor tangent: The line in the toast about "siren of the deepest void" can be interpreted as being a Whale (siren) within a sea / ocean (deepest void).
In mythology Cetus was generally any kind of sea monster, typically a whale.
Perseus had slain a sea monster, turning it to stone with Medusa's head, to save the princess Andromeda from Poseidon. An alternate version had him slay it with a 'harpē' or type of sword / sickle.
MB's Legacy novel's description of Julia's childhood book was of "a young man’s quest to save a princess from an alien dragon".
Sea monster / sea serpent / sea dragon, the terms are very interchangeable in mythological context.
Another mythological 'sea monster' is the whirlpools associated with Charybdis and Scylla - where characters such as Odysseus and Jason were stuck with the choice of literally a rock and a hard place to navigate a narrow treacherous strait. Like you pointed out in your linked post, a relationship with Lyra, Orpheus and quelling the sirens to allow safe passage. The 'Summer Triangle' of Vega, Altair and Deneb is an asterism used for navigation, and each star are the brightest of their corresponding constellations - Aquila (eagle), Cydnus (swan) and Lyra (lyre / harp).
Perhaps there is a dangerous challenge for us to embark on, navigating through a 'narrow strait' ... in other words a P A S S, seeking the jewel on the brow of the mother of galaxies.
Related note: The Cetus constellation sits within the "sea" of water constellations - Eridanus, Pisces, Piscis Austrinus and Aquarius.
Also, the Cete (ie. whale) megaship is deep within the Guardian bubble.