it's also very shallow
You take that back!
In all seriousness, if you're talking about something like the fact that all machines are functionally doing the same thing, that's kinda fair, but there's a lot of complexity in all the options available, made even greater with DLC and mods. Just the logistics of getting items to the right places have many different approaches with various upsides and downsides, and I love all the emergent mechanics that come from belts having two sides and splitters handling two belts.
It's not a game for everyone, but calling Factorio shallow seems really odd. If anything, I feel like it allows you to explore its mechanics deeply, instead of having a breadth of shallow mechanics that don't leave anything to be discovered.
I haven't properly tried satisfactory, I tried the demo back when that first came out, was asked to run around collecting leaves to put into a power generator for half an hour, and bricked my game trying to put it into borderless or something... And then I switched to Linux, the game was epic exclusive despite promises otherwise, and I passed.
I got the impression it's got a tedious early game, having a prebuilt map might make replaying less fun, and it sadly seems to have a very point-to-point, purpose-specific-device approach to logistics. I also like the performance of Factorio, it's really lightweight on the GPU, and well optimized for CPU (though with the entire map and tons of individual entities loaded at all times there's only so much you can do), which I imagine isn't as great for the modern 3D game Satisfactory is.
I don't want to rant too much about it, but I think the splitter taking in and outputting two belts in Factorio is brilliant. There's only a few types of logistics, but they are versatile and nuanced. Being able to belt items onto the side of an underground belt lets you filter out belts by side, the mechanics of belt sides and how they interact with inserters let you create compact designs or maximize throughput if you spend time on it. There's no dedicated buffer machine, no separate splitters and mergers, all the neat things you can build come together out of component parts in an organic way.
I will also mention that I like to try to plan ahead specifically to avoid starting over, but when rebuilding is necessary (and when laying a rail network) robots are a must-have.
On the topic of the DLC... If you're not drawn into the base game, might be best to pass on it, but they did a good job giving each planet some interesting unique challenges, including organic items that spoil after a certain amount of time. There's plenty of straight content expansion mods, big and popular ones, but they mixed up the gameplay quite a bit in Space Age.
All in all... Yeah, different people, different tastes. I'm currently doing a second playthrough of Space Age with friends, but one of them might've been felled by Gleba. If you want some more unsolicited gaming takes, I can recommend Mindustry and Outer Wilds ;D