Recording Presentations with OBS and a Bluetooth Mic
You could get a Sennheiser ClipMic, plug it into a cell phone, and then establish a Bluetooth connection between the cell phone and the Laptop.  I can't give any first-hand recommendations on best practices for Bluetooth audio streaming for live mics (I think most professionals prefer dedicated RF equipment to BT), but it does seem like there are options available.  Here's one that came up in a google search for "cell phone bluetooth PC audio microphone" without quotes.