I haven't played Nexus, but from looking into it. The story in Nexus is better, but the gameplay improvements in Unknown Space make it feel much better to play. The two games are totally separate in terms of story so you don't have to play one before the other or anything like that. Its likely that Ill end up grabbing Nexus before the sale is over since I really really liked Unknown Space.
I was going to ask that. I played "Unknown Space" a few months back. And i would say: It handles and looks a bit better than "Nexus", but the main mystery, the small encounter-stories on planets and the aliens were better in Nexus. Everything had a bit more character.
In "Unknown Space" i was bored after a while, just checking off planets and side quests, but weren't invested in it at the end. The "memetic?" religion and it's followers were a bit too nebulous and impersonal as a threat. Wanted more of it. More explanations AND mysteries, maybe a real face of the threat. Wasn't that developed.
Um so i bought myself "Terra Invicta" after waiting for quite a while on it. Thought it would fit my gaming very well: Global interactions of multiple factions/forces, long planning strategies, pausing at will to check data und refine strategy, science-fiction plot.
So... i got bored by the game real fast. Didn't click with me. Started a new run as the faction which welcomes the alien invaders and works with them: barely anything changes - got bored again.
This game REALLY needed more and better flavour-text with the missions, more agency by the states. More shifting goals and curveballs, more options and decisions for the player... I don't know... didn't get me.
Played around a bit with Cosmoteer. Fun, but limited game. You build/rebuild and command a spaceship. So far not much of story. You just do quests for Money and ressources and build bigger ships and do more dangerous quests (Go somewhere and blow someone up)
Main thing: You have to design the ship with staff in mind too. You can have different crews (All the same skills, but different "jobs/stations") and have to put their barracks, and they need to get to where they are needed. Damage destroys/knocks out systems and corridors complicating managing everything. Neat.
Overall: Have i missed any good games where i manage a "single entity" (A Cult, Spaceship, Organisation, Kingdom, Professional Kickboxer - whatever) but don't have to micromanage shit - with a clever, open world, and preferable a pause function? Was looking for something like my big other timesinks of my past (Starsector, Mount & Blade, Crusader Kings, The Guild) Played a tiny bit of Ostriv and Manor Lords last year... but they need a bit more time in the oven, i guess.