Stellaris, in particular, might be up your alley.

I like Stellaris quite a bit, but I should note that OP mentioned how he didn’t like spending money on DLC. Stellaris follows the typical Paradox approach of creating a lot of DLC to expand and extend the game as long as people are interested in buying it, and winding up with a large game that’ll cost you a lot if you want all the DLC. It may be worthwhile, but if one wants to get all the DLC, it’s gonna add a fair bit to the price.

(checks Steam)

The base game is $40. Buying every available piece of DLC is another $429.