The Githyanki Main

Given the fore-grounding of the githyanki presence on the Astral over the past couple of editions and in Baldurs Gate 3 - and given the new structure of the multiverse with all material plane systems floating as bubbles in the Astral, this makes them the 'universal' power - omnipresent but not omnipotent.

Going with 'Activities on the Astral' from 2e 'A Guide to the Astral Plane' we have explorers kicking about and hunting expeditions, essence mining on some select few dead gods and lots of attention to military patrols and campaigns. The primary foes for all this military activity are the githzerai and the illithids.

I thought a good model for this would be the Spanish in the Age of Piracy, an empire where reach has exceeded grasp - claiming all the astral but being a finite, if mighty, power. For inspiration, see the Spanish as portrayed in Pirates of the Carribean: On Stranger Tides. They seem like a decent model - relatively competent, fanatical, directed on religious grounds by a distant leader acting through devoted agents, lots of resources where they bring them to bear - a fearsome enough threat.

If we run with this analogy - mostly to get a sense of what the 'pulse' of the Empire is when things are just ticking along then we have a few parallels and a few differences.

Parallels
Treasure galleons - with Vlaakith on her throne serving as the draw for essence from scattered dead gods or booty from raids and conquests by her faithful - use all your treasure fleet tropes - incredibly valuable, very well guarded
Lost treasures - psychic storms, astral dreadnaughts, all these are hazards that could wreck an astral skiff and then roaming colour pools could see it cast somewhere odd on the planes
Treasure maps - grizzled githyanki survivors clawing their way back from being stranded on some Vlaakith-forsaken prime with a map of where their ship went down
A few big hammers - become enough of a nuisance and you will have nightmarish resources sent after you but conversely power is highly centralised and there are mostly bigger fish to fry
Not enough hands - For my own Spelljammer campaign I had my party set up with Letters of Marque to patrol/investigate various doings in the far flung reaches of the astral - from the Githyanki point of view they have regions of the astral that are not of critical interest to Vlaakith and so lightly held, where the local commanders need to draw on mercenary crews or wandering adventurers to keep tabs on things.
Hot and cold politics - depending on whether an envoy from the crown is present, those present in whatever far-flung outpost will indulge in less back stabbing for personal gain, plenty of 'more righteous than thou' front stabbing perceived weakness in the face of Vlaakiths will. Should an envoy with direct instructions from the lich queen arrive, people will fall in line

Differences
Hunting (astral-whaling) - long haul hunting voyages are a couple of centuries later strictly, but they are still age of sail so they work
Conquest of the locals - most sources talking about the githyanki make no mention of non-githyanki; implying they wipe out or drive off anyone they run into when they take new territories