Honestly? Minecraft vanilla. Partially because it is not an automation game at it's core.
I enjoyed peppering our lands with automated chicken cookers, cactus farms in the sky, gold farms exploiting portal mechanics, and of course an automated transport system.
That it's an game of endless exploration meant I could redo the same (or similar) designs all over when we moved to a new region, and still visit the old machines on journeys.
It was fun to think about how regional peculiarities and peculiarities of specific blocks could be combined to achieve certain outcomes.
I played a lot of Satisfactory, it’s awesome, especially in multiplayer. I also dabbled a bit into Dyson Sphere Program, also quite fun, cause of the different perspective and the whole planetary aspect. Haven’t played it for a while though, no idea about the current state of the game.
Still a great game, both gameplay as well as technically speaking. Every time I fire up my old save game I'm amazed again how well it runs on my machine even with tons of things going on.
Definitely Satisfactory. They've been consistently setting a gold standard for developer openness and communication, just as much as Factorio did. And the game is great, too.
I'm a big fan of Satisfactory, but there are others I've been trying too.
Techtonica is an interesting premise, sort of "Satisfactory In A Cave", and research produces a bulky waste product that you have to store somewhere, but digging out a large enough cave to get any kind of decent factory built takes forever. It's still early access so stuff may change.
Oxygen not Included. You get a few clones on an asteroid and have to keep them alive. You can survive without automation but barely. The automation stuff is mostly circuits you build in order to not waste power.
You end up building nightmare spegetti monster machines because your fucked up and opened a volcano 20 hours ago and the only thing stopping your base from getting to hot to grow food is the toilet water getting dumped into the new steam chamber.
At begin is challenging but at end i realize that is actually all about resources that can be very limited. You can keep going for even 1000 cycles without know your game failed at 100. I wish was more istructive with better direction, too much freedom is fun at begin but terrible at endgame.
Captain of Industry has been my recent favorite. It has very elaborate productions chains, and it has terrain manipulation that forces you to actually mine for resources and dump rock and slag in the sea for more land.
I liked prison architect, rimworld and oxigen not included. But everyone lack of something, they are limiteded by frustrating progress that make me as player feeling exhausted after one or two projects. While factorio have actually a good automation and line of program.
Dyson sphere program. You just need a little bit of space to be able to retroactively add belts into existing stuff because of the 3d belt placement and logistic drones are cheap, so you can ship loads of stuff with them. It lends itself wonderfully to spaghetti factories, which is my favorite kind of factory.
It's also absolutely beautiful. You can just stop and watch the glowy cubes flow at night or witness an incredible sunrise over the factory. And that gets better as you progress because, well, you're building a dyson sphere.