There is indeed a whole “simulation” sub-genre of games based on that paradigm, yes!
Satisfactory is a nice Unreal Engine based factory simulator; Factorio is the classic 2D based game in the same vein.
Most of the “sim city” / “cities skylines” type games use a similar system for water, electricity, and roads.
On Roblox, there are many “miner tycoon” type games that do something similar, one way or another.
And then there are Zachtronics games like SpaceChem and Opus Magnum and Shenzhen I/O and …
Anyway, NGSpice isn’t “integrated with Unreal Engine” but it is open source, and you can probably break into the library in an appropriate place, to configure it with the components/models you want, and run some number of simulation iterations per game frame. Most third party libraries can be made to work by starting them in another thread, and pushing a little message queue of some sort into the middle, where you can post a message from the game to read state out, or control how they otherwise run.