Small smartphone like iPhone SE1 (speakers + echo-cancelling mics) mounted on a boom mike stand , e.g. https://www.amazon.com/gp/product/B07V2FJL54/
Polycom desktop speakerphone would have more range, but it's larger and you'll risk picking up audio from neighboring cubicles.
If you want something more precise, use a small directional microphone, e.g. Rode has one that plugs directly into an iPhone, https://www.apple.com/shop/product/HMG72ZM/A/røde-microphone...
The issue is the speaker btw not the mic. I want(ed) it to be outside of my ear as in the bluetooth wearable headsets though.
Directional speakers:
Commercial, https://www.holosonics.com/products-x
2023, https://www.kickstarter.com/projects/1252022192/focusound-th...
2018, https://www.kickstarter.com/projects/richardhaberkern/soundl...
2017, https://www.kickstarter.com/projects/richardhaberkern/soundl...