you're saying it as if imperalism is bad....
You don't need to have a superb memory, just be a specialist in an engineering field or simply interested.
Yes, a lot of developments need prerequisites, but you can develop those, or are you telling me you don't know the process to make a blast furnace?, or a steam engine?, unless MC is a complete ignorant muppet.
A lot of isekai tackle this beautifully, where MC advanced the technology be leaps and bounds (efficient waterwheels using prime numbered gearing for example), mass production of iron and steel, blast fur, advanced sanitation/plumbing. That's what i like to see, MC using advanced modern engineering knowledge to rapidly industrialize the setting.
the isekai where MC does not take advantage of their modern knowledge are wasted opportunities
Imperialism is pretty bad for everyone outside the imperial core.
I also think you're severely underestimating how much foundational work goes into recreating industrial technology. Have you read "The Perfectionists" by Simon Winchester? He discusses how early attempts at iron power transfer machines in the late 18th century (like James Watt's steam engine) were incredibly inefficient because the machining technology didn't have tight tolerance capabilities. It wasn't until John Wilkerson invented a boring machine capable of putting a straight hole through a block of iron that a usable steam engine was created.
In terms of an isekai, you'd have to first know the concept of a machine you wanted to create, then know the technical skills needed to create that machine, then have access to the material production technology to get the stuff to make the machine, then have the charisma to organize a team of laborers to stop growing food to help build a machine they've never seen before. If you don't have one of those things, you have to spend a long time using trial and error to figure it out.
Another issue is that industrial society creates specialists rather than generalists. It's rare to find adults who have more than surface level knowledge outside of their specific field. A chemist might be able to create fuel, but would they know how to farm or mine for materials, or how to blow glass for distillation? A machinist might know how to build a lathe, but do they know how to turn iron sand into carbide steel tooling? An individual with modern knowledge would need collaborators to put industrial knowledge to practical use.
Taking it back to this story, Ars is an office worker. He knows how to be a cog in a bureaucracy. He does use his modern knowledge, it's just that he has some ideas on organizing people instead of manufacturing or design knowledge.
