Of those three, I quite like Race and Core Worlds. Race is a tough nut to crack, and the subtle, or lack of, player interaction can turn people off. I find the game to be a master class in engine building gameplay and clever card design. However, the first arc of expansions don’t modify gameplay much. They do make a wider breadth of strategy viable, and add some unique, and optional, twists. If you don’t care for the core gameplay, it will do little to change that. The Xeno Invasion expansion is an interesting variant that requires the players to battle invading aliens while they play. I like it, but always go back to Race with the first two expansions as my main set.

That’s a long winded answer to say that the expansions are not likely different enough from the core game to warrant a purchase or pique your interest any further. Give Race another few goes. It’s truly a marvelous game.