There was an ancient war between two advanced alien civilizations that culminated in a battle over Earth. These two armies destroyed themselves in this final battle, but the fallout indirectly ravaged the planet. As a result, earth has become a wasteland stuck in the dark ages, filled with genocide, slavery, starvation, and all the usual horrors of warfare on a global level. Civilization has regressed back into tribes, each struggling to survive after the apocalypse. This state has lasted for thousands of years.
This battle left space debris orbiting the planet, which occasionally falls down to earth. This debris usually contains advanced technology and weaponry, which the inhabitants constantly battle over. The result is a planet occupied by techno-barbarian tribes, each fighting the other for access to this tech and domination over their enemies.
Civilization is a hash of various, barely understood tech. Vat-grown abominations made from artificial wombs, cybernetically enhanced amazons, genetically enhanced soldiers, machine drones controlled by A.I., the list goes on. History is filled with various empires rising and falling in quick succession, followed by periods of dark ages.
In this chaos, one city state has managed to remain stable through the various millennia by hoarding as much tech as possible. They have gathered the most consistent forms of technology through organization and study. As a result, this city state has the most knowledge and understanding of the tech they use.
It wishes to remain neutral in the various wars raging around the planet, and do not take part in the chaos. They are unaligned with any faction, and do not take sides in conflict. To preserve this neutrality, they have agreed to trade technology with various tribes so that all would see a benefit to letting this stare operate. However, While they are powerful, they are tiny compared to the tribes roaming the planet, who could destroy them given enough time. It is well known how this state hoards technology, and is sitting on a vast pile of advanced tech that would make any tribe vastly powerful, perhaps enough to build a long sustaining empire. a strong enough techno-barbarian with enough allies could potentially overthrow the state and take what they have simply with strength of numbers and more technology.
In this world where control and domination of technology is the most important thing, how can this state remain neutral and protect itself?