Wireless microphone system for giving lectures
I had the same problem.  To make me quit complaining, the department chair bought a RevoLabs USB wireless microphone.  I kept it in my office, plugged in to a USB charger wall wart, and took it to classes with me.

I'm still teaching a bit, even though I've retired, but the RevoLabs mic somehow "became lost" after I turned it in.  A new one is too pricey for me to buy at over $200, so I bought a "Fifine" USB wireless mic from Amazon.  It's neither as high quality nor as unobtrusive as the RevoLabs mic, but it's also $40 and works fine.

My use case is recording my lectures with PowerPoint; I then post a "narrated slides" video for students who missed the lecture.