The patent for negative feedback was rejected as "another perpetual motion machine" - I’d never heard this! Do you have a reference so I can read more?
https://wiki.epfl.ch/me412-emem-2020/documents/06501721.pdf
The difficulty with the patent office is on the last page.
You can find an old edition freely available here: https://archive.org/details/TheArtOfElectronics/Vol-1/mode/1...