Factorio has been supported by its developers for the long haul. It could easily have been called complete a couple of years ago.
I've got well over 500 hours on the game. It's never crashed and I've only ever encountered one bug when not using mods. A furnace was outputting its fuel rather than the stone bricks it was supposed to be creating. I deleted it, replaced it and it ran fine. Took about 10 seconds to fix and never re-occurred,

The game is deep. Creating you factory is a bit like programming - creating an app. Iterations, inputs, variables and bugs (in the form of biters that attack your factory)
I don't try and min/max though many do. I prefer to be creative, for what happens to be unique and my own. I'm probably only 75% as efficient as some other players - but I don;t care. Copying someone else's formulas .. it's almost like letting someone else play the game for you. Creating your own stuff is most of the fun.

Look - the gane is fantastic. It has so many mods that even when you've completed the base game you can do whatever you want. Someone created a music video by programming the electronics from a factory to trigger individual screen pixels once you zoomed out far enough. I kid you not.
If creativity, programming, sand box puzzles where there are almost infinite solutions to any problem - but some better than others. If that appeals to you. Just buy this game.