There’s an argument to be made that the Black Death broke Europe (or especially Britain) out of a local minimum, by killing off labor. This reduced the necessary rate of return to physical capital and innovation. (Why invest in an iron plow, when you can just set more serfs to the task with wooden ones?) and ultimately this planted the seeds of the industrial revolution.

though Hero’s engine is a steam engine, it is practically useless as anything besides a curiosity and certainly could not have powered an industrial revolution

Yes, but I am confident if there would have been demand, they would have improved on it. It can open temple doors so I do not think it is too far away from a useful machine.