An engineering game, as I'd define it, is a game where a primary gameplay element is designing machines for some purpose, weighing conflicting needs such as cost, versatility, and performance. I've only played a handful of these games, and I really wish I could find more. Here are some of the ones I've enjoyed:
Kerbal Space Program: I'd call this a definitive example of an engineering game, and one I have hundreds of hours in. I absolutely love designing rockets, figuring out what I'll need for each mission, experimenting with different staging mechanisms to maximize fuel efficiency, pushing my available tools to the absolute limit to land on far-off celestial bodies, etc.
Automation: The Car Company Tycoon Game: Yes, I know, fuck cars, but I'm having fun with this one. There are a lot of different niches you can cater to, and I enjoy specializing in affordable, reliable, fuel-efficient sedans and compact cars against the trend of turning everything into a gas-guzzling behemoth.
Master of Orion: Yes, a DOS game from 1994, and primarily a 4x, but its ship designer has some of the best balance between simplicity and depth I've ever seen. Ships have a limited hull capacity, but no fixed number of weapon hardpoints, and they can only fit a handful of special modules, but there are dozens to choose from, with widely varying capabilities. The number of actual choices to make is small, but they involve balancing so many things - durability, damage reduction, damage output, armor penetration, weapon range, maneuverability - and the turn-based combat gives enough control to let you really appreciate the impact your designs have.
Avorion: A space flight sim with highly customizable ships built out of blocks, with fine-grained control over things like engine power, maneuver thrusters, and armor thickness, and cargo bay sizes. I wanted to like this one, but it's way too grindy for me (building up your reputation with factions takes forever, and they won't let you buy better ship equipment until you do).
Robocraft: A game where you design a robot and then pit it against other players' creations in online team battles. My best creations were a spider bot that could scuttle up and over hills and ambush enemies with a massive plasma burst, and an air defense bot with bigass twin AAGs and a shitload of top armor. I had a lot of fun with this one back in the day, but nowadays it's so deserted that most of the players are bots.
So Factorio would be like the ur-example. It's all about producing very complicated factories. The dev is a squidnozzle so pirate without remorse
Dyson Sphere Program is a cool game about, well, building a Dyson sphere. You have to build huge factories across multiple planets or even star systems to harness the power of the sphere (or swarm). A recent update added an enemy to fight if you're in to that, but you very much just can build and build and build and build and build
Gratuitous Space Battles is an ancient auto-battler where you build a fleet of ships using various hulls and components then set them up, give them orders, and watch them fight it out with the enemy fleet. There's lots of options and setting up synergies between ships and taking advantage of enemy weaknesses is important
I think Ostranauts might have this but honestly I have bounced off this game like a brick wall, it's complex.
Outpost Infinity Siege isn't this, it's a weird combination of FPS, extraction shooter, tower defense, base management, and a couple of other htings. But the core loop is - explore, loot stuff, defend your tower to extract stuff, return to base, build new stuff for your tower, then repeat. You have lots of building pieces, machines, turrets, utilities, and so forth you can add to your tower, and it can get quite complex as you try to balance armor, utilities, power, ammunition, while setting up all your turrets for optimum fields of fire and coverage. I've spent hours and hours building and tweaking my base. Late game you can set up an ammunition factory, too. There have been many quality of life updates since launch that have made progression much faster and more reliable so it's easier to get in to now that at launch. Really unique game, there isn't anything else like it.
A big part of X4: Foundations is building stations, assigning ships to convey resources and products between them, building large factory complexes, setting up trade with the various factions, and managing your tech. It's really it's own thing, a very big, complicated, messy space capitalism sandbox. Not nearly as complex as Factorio but I did end up with a bunch of spreadsheets to track my fleets, my station inputs and outputs, and so forth.
Besieged is a fun old doohickey building game. Your task is to blow up a castle or tower or some sheep and the game gives you tons of mechanisms and doodads to stick together. Once you've built your machine you turn the simulation on and watch the chaos.
Nebulous: Fleet Command is more or less "The Expanse: The Video Game". It's a very granular space combat sim where you design ships, assemble your fleet and go to war in a PvP environment. radar coverage, E-war, jamming, point defense, very granular resource management, and shooting shipping containers full of explosives in huge salvos are all key to gameplay. It's very very cool.
Rimworld can be this. You're mostly ordering around your little dudes, but they work a lot like semi-autonomous machines. It's much much more approachable than the very similar Dorf Fortress.
Astroneer has elements of this but it's mostly exploring.
With the right mods Fallout IV can involve building a lot of complex gadgets and whatsits to produce resources at your settlements.