Note: the keys would obviously not be there all the time, it'll be explained when the player just enters and gets the game's basic info. This will help with not only fulfilling the multi-planetary theme but also with mapping. It'll all be worth it in the end.
Katyusha Synth TSW OST... Also keep in mind this is a rough draft, not a final product. ofc it'll look bad for a hoi4 mod. This system seems to make the most sense to me tbh.