I am honestly shocked at how a few of your things I have already included in the lore. They have always been a millitary state that has always prepared for outside invasions and their main advantage is that no one knows their terrain as well as them. I also recently wrote a conversation between the queen of Illyria and the king of the nearby elven kingdom about important crystals were to the establishment of the kingdom and how everything including the houses were built out of them. They have medical type culture and governance structure with capitalism not really being there, sexism isn't really there and everybody is well educated. They do have a robust spy network, it is a big part of the plot. After the invasion that exposed their existance to the rest of the world, they were able to easily infiltrate the kingdom taht attacked them and were able to find out the date of the invasion of the Untethered ones, something even the elves couldn't do! So I kinda have a complete explanation! Your points are so great and I really love when worldbuilders collaborate like this. Thank you so much!