How to create an inset for a mixer knob with boolean?

I need to add a mixer knob to a panel algorithmically because I want to be able to easily copy and paste this knob around the panel, but I can’t figure out how to do it effectively. Here is my attempt and you’ll see the issue.
mixer knob inset fail.blend (173.8 KB)

Here’s what I’m trying to make:

You alsmost got it: you use the cube as a negative boolean but the topology is wrong see:


Left is yours with a bit tweaking to see egdeflow, right is mine. Just raised the upper plate add selection and lowered the whole thing… also used fast boolean