Sins Of A Solar Empire is described as 'Explore real-time interstellar battles blending 4X strategy, customizable fleets, dynamic maps, and diplomacy with resource management across vast galaxies' and is a RTS game in the games category. There are more than 10 games similar to Sins Of A Solar Empire for a variety of platforms, including Windows, Steam, Linux, Android and Web-based apps. The best Sins Of A Solar Empire alternative is Endless Space. It's not free, so if you're looking for a free alternative, you could try Planet Capture or Edgeworld. Other Sins Of A Solar Empire like games are Stellaris, Battlestar Galactica Deadlock, Galactic Civilizations and Homeworld.
Its not RTS and way more complex