I think anyone with a halfway decent pre 1990 high school education could make major improvements. After all, most of us have a decent understanding of the basic principles of flight and how a combustion engine works. We know about germs and the importance of sanitation.
I could probably come up with a rudimentary generator to run off a water wheel.
I think it would end up being a very different world today.
“I could probably come up with a rudimentary generator “
once you invented copper wire and an insulator, yes. What would you do with the electric power?
You will have better luck with electrostatics.
Materials, tool and die would be the problem. Medical and sanitation would be improvements. Force multipliers should be simple to build but then we are back to the original problem. Consider, I want to build a simple low pressure boiler. To do so I need to be able to weld or solider. For that I need point heating. So let’s say I know how to make acetylene. How would I compress it? If I could compress it how could I store it? See how the issues compound? And how would I not get burned at the stake for witchcraft?