Earlier quoted context omitted.
I felt the same way for a while (this is FUN, this isn't work!), but at one point I came back to the game after a few months off, started a new factory, got to something like "automate green circuits", and immediately felt like I was back to battling some NPM dependency. It had lost all its magic and suddenly felt like work again. This was after about 300 hours of playtime over a few years, but I haven't really been…
The biggest hurdle for me getting back in is just getting past the bootstrapping phase to where you can automate the construction of things from blueprints. Luckily the game is made overwhelmingly with mods in mind, so there is a mod for my issue.
First playthrough I was anxious to get to the automation parts. This continued as I explored more of the game, more of the automation possibilities, blueprinting, trying to make an all solar, all steam or all nuclear factory etc.
At some point and I don't know when exactly it turned. I like the initial bootstrapping phase and at varying points I just get this "ugh, really? This pre-requisite, then this, then this and then finally I can build what I really want?" and then I shut it down and play Dungeon Keeper 2 or something like that instead.