So for context, a quarter century ago now, the RTS game Age of Empires II: The Conquerors Expansion allowed for creating custom AI scripts for its computer players.
This suggestion proposes the same. The addition of an interface through which custom strategic AI scripts can be used in campaign. If an AI has a custom AI script, the script will run continuously, evaluate its available resources, and give commands to its fleets as well as spawn commands.
Information that would need to be exposed to the AI interface might include locations of all known resource zones, locations and stats (resources, speed, fuel usage, firepower ratings, health, etc.) of all of its own and all known ally / enemy fleets, terrain heights, and maybe even commodities; and the AI interface would ideally also have the option to task any fleet it has to any location including on patrol loops, merge or split its fleets, spawn and scrap vehicles. It might be best to also give it "cheat" options such as revealing the map to itself, providing free material/energy to its fleets (or if it's allowed commodities, refilling its commodities for free), and so on, as many but not all RTS AI have these abilities.
Obviously, I don't expect this to be a minor update. If this were to be implemented, I would be surprised if it weren't a more serious update than any of the post-release weapon systems. I'd hope it would be less work than updating strategic AI wholesale, while also making it possible to make custom planets' campaign AI behaviors more complex and varied.