Solution 9 - Unfounded Speculation!

[Denishia]

I'm going to stake my flag of pure speculation on: It's homegrown Turali. A few centuries ago, a thousand or few at most, or even recently, people in North Tural were able to advance their technology to this cyberpunk-esque state because they had plenty of lightning aether and ceruleum to work with. And for outside help at most they uncovered some Ancient ruins to use as inspiration but instead of Creation Magic to summon concepts like the Benthos Ondo, went in a completely new direction. Ascians didn't wipe them out because they didn't have a Lightning-aspected Calamity scheduled yet and also miffed and ignoring them because whatever they were don't wouldn't matter when the Final Rejoining removed them and those people weren't recreating the homeland in the right way anyway. The place has a strong Digital Upload SF vibes, very Ea-like in end goal. Or, in a fun reversal of the Terra of IX and the most popular current theory- the souls trying to move over to another Shard are from the Source/Tural and Solution Nine is part of the attempt to transfer their souls to one of the Shards, maybe in a misunderstanding of how to escape Calamities/the Final Days. For deep dramatic irony.
Most society-leveling Calamities have a lessened impact the further out from Eorzea's epicenter one goes, according to SB, so North Tural was free to advance their tech in the past until something else culturally made them reject it and the Federation that governs Tural from Tuliyollal replaced it except for this enclave up north.