I love stellaris. Very deep strategy with a good amount of variety and a ton of mods. The only thing about it is if you want achievements you have to play in 'ironman' mode - no player saves, just autosave. There's nothing worse than getting 3 hours into a game, making an error in the type of fleet you built, and getting destroyed by a neighbor. Still, it makes the game interesting and impactful all the way through.
Paradox games are like that. I love their work, but their DLC policy is garbage. Europa Universalis 4? They are still cranking out DLC and the mod community for all of Paradox's games is ridiculously deep.