I'v been experimenting with trying to make a smaller Electron like Javascript application wrapper. It's called Shrinkray, and only adds 60K of overhead to the size of the app. See: https://github.com/francoislaberge/shrinkray

It is macOS only (for now). I haven't measured if it is more performant when in the background, but I will. It'seems certainly way smaller in disk size, but comes with tradeoffs in API/functionality.