Fellow docs person here. Really like the new design—both in terms of information architecture and actually browsing the site! It looks like your docs engine is based on Gatsby. I'm looking into replacing our current static site generator, and Gatsby's near the top of the potential list.
I haven't dug into the repo yet, but building your own docs engine atop Gatsby seems like it would require a lot of additional config. Any major things you needed to address that Gatsby couldn't do out of the box? And when you say further use of the docs engine, are you open to other organizations using/tweaking it?