Starcom: Nexus temporarily scratched this particular itch for me. There is no economy in the game, but there is ship building, researching, collecting resources, interacting with ships and planets, discovering stuff, space battles and a mystery that takes 10-15 hours to unravel. It's a top-down 2D game with free movement. The gameplay is balanced and fun, and the game doesn't always give you quest markers to chase, so you are expected to be observant.

https://store.steampowered.com/app/863590/Starcom_Nexus/