It's a mix of strategy and role-playing. Sure if you want to survive on higher difficulties, you probably need a build that is meta. But on medium difficulties or lower you can pretty much roleplay your empire as you like and there's many mechanics in the game that help with this. Your empire can be a democratic haven for all, a mega corporation, a machine hivemind forcefully assimilating organics into its network...and much more.

There's also a great exploration aspect of the game. Your exploration vessels regularly find anomalies that tell a neat little story and provide bonuses to your empire (which can range from a small resource bonus to making one of your leaders immortal).

Of course, there's also the power fantasy. You start with just one planet, but you will quickly expand throughout the galaxy. You can then wage war against other empires, build a federation together with them or convince the galactic community to crown you as Emperor of the entire galaxy. But the game also regularly throws adversaries at you if the AI empires are starting to become no match for you, may it be one of the space fauna suddenly becoming extremely hostile or a Great Khan uniting a marauder horde and demanding everyone to become their vassal.

It is also rare that a bad outcome leads to a straight loss. Losing a war (usually) does not doom your empire but you only lose a bit of territory or get vassalized, both giving you ample opportunities to build up your strength again or make allies to stand together against an enemy.