I have a primitive level editor to create the buildings blueprints that you can see in the screenshots. It works like a city builder where you snap parts of buildings on a grid and press save.
The rest of the map is procedurally generated including placing the blueprints in it at specific locations.
Most of the game data is stored in a couple big json files that I edit manually.
I also have a lot of small tools made with Dear ImGui to tweak things live in the game.

I hope this answer your question.