I think the best game in that genre myself is Space Empires IV I've played them right through SEII, SEIII and now SEIV
Such an in depth game and take ages
you research, put together your own ships, they need refuelling, resupplying, repairing, then you have to decide what needs mothballing, what needs retrofitting, what needs upgrading
you have fighters, mines, starbases, construction yards, scouts, cloaks, you can dstroy planets, stars, nebula, you can create new warp gate, destroy them the list goes on
always fun when yoiu're about to be overrun and you simply destroy the warp gate leading to your system leaving you isolated
It is available over Steam as a paid downlaod as well