For building vast structures, to me it's mostly Space Engineers, but that's another concept too, not exactly "build a gigafactory" type game. Still, building something big and cool it does.

I'm also sad MMOs are rarely first-person. Like, there was Tera, but it died immediately as I first heard of it, which is super unfortunate because it certainly seemed to tick my boxes.

I didn't play The Talos Principle, but heard about the game. Spent quite a while in both Portal games though - good times.