Old ones are potential creators of the realms, the pole gates in the old world are actually just realmgates
The technology of seraphon is incredibly advanced. To them miniature realmgates are just like daily tools, there are multiple small realm gates in one temple-city, and the ark of Sotek is actually a very small realm gate.
Their mothership can be broken up into several small ships to land as the foundation of temple-city. When they land the majority of the ship will phase into the ground, the soil replaced will be directly teleported into space. Basically these spaceships are like world ship in sci-fi works, have everything from environmental engine to self-replicate building systems. All worship of old-ones, like tepok, is passed on, they are now just traditional lizardsmen with higher tech and magic. It is also mentioned during the time of Old World, their pyramids were actually under auto-construction all the time, and only finished all the remould in time during ET.
Sunblood and Eternal Warden are hinted to be fragments of characters what they once were(old Lizardmen characters) reborn into life through spawning
Many of mortal empires in age of myth which had incredibly advanced technology or arcane technology is a result of relic of old ones bestowed to them by Slann.