It does feel like work, but that's okay! Some mechanics are mundane than others, e.g. compare clearing enemy bases to designing rail blueprints, but the game does everything to make it efficient and ejoyable: high performance, keyboard shortcuts, immense amount of quality of life features - all you get when devs love playing the game themselves.

And, even Factorio being my favorite game, I still need to take a long breaks from it because building a factory is a lot of mental effort.