This is just an illustration of a possible technique we could use to get some extra contrast between icons and their backgrounds. And also to have a "disabled" state that differs more from "off" state.
First there are automatic outlines. There is no configuration as I could find no situation where it caused harm. In a nutshell, every time an icon is drawn there is first a background outline drawn in a contrasting color. The outline is slightly larger than the icon (naturally) but it is sized that it will always fit within existing widgets without looking crowded.
A sample of what this looks like when at 2X scale size:
But it does still look nice at 1X size:
For disabled icon state it is also automatic, so no configuration needed. It is like the outlines, but instead of drawing a larger background outline it draws two copies of the icon, both dim, in contrasting colors, slightly offset from each other.
It looks like the bottom half of each section below: