Hey @WikiWick, nice to have you here.
One important thing: Unity is only used to create the 3D asset bundles. It has nothing to do with scripts or configs. So that’s why there is no menu in Unity, it doesn’t know anything about the game at all.
For script mods, you have to follow this tutorial: InfraSpace Modding Tutorial: Introduction to Script Mods
Which means compiling the mod into a .dll and then running that with the game.
@BaYoNeTTe is probably the most experienced modder, maybe he has advice if you have more questions. He is also on Discord.