It would be great to do a true RPG experience with a game like Civ V or Civ VI (or anything similar). Problem is, the AI sucks in the Civ series, so almost universally they start getting nasty and insulting, whether it's my military that's stronger or, more likely, my economy is the largest of all other Civs. I hate it when relations suddenly turn sour for no reason - I establish trade routes, try to have positive diplomatic dialogues, but it never seems to matter; they always get mad.
Flawed as they are in other ways, one thing I appreciate about both Paradox and Stardock games (including Stellaris, GalCiv3, and FE:LH) is that when you're stronger than someone else, they're actually more likely to be nice to you. It makes role-playing your faction (which I do as well) a bit easier.