I mean.... Welcome to 4x! There's so very much out there. Have you really played no sid Meier's civilization? That's just a half step up on the empire building complexity (and a quarter step down on combat, which you don't have much interest in if I understand correctly.) there are a number of other civilization inspired games that are coming out right now, as well as some older ones that have a different spin on the civ framework (I don't have a list in front of me). Galactic civilization 3 is another half step deeper into the empire building genre, Stellaris and sins of a solar empire are also rubbing elbows with greatness of space 4x (sins is a very slow rts which might be intriguing to you). Back on earth we go for the much more involved 4x, crusader Kings, Victoria, and Europa universallis, those are entries that will make creative assembly, and their total war series, look like children playing with blocks and a peg board.