What is the best webcam for MacBook Air M2 running macOS 10.14?

if you don't care for the webcam build into the MacBook air

and don't wish to use an iPhone as webcam Use your iPhone as a webcam on Mac - Apple Support

then if it was me then I would look at logitechs cams I've had much success with them

What does "best" mean to you? Older webcams are not supported for what exactly? What exact requirements do you have for video recording lengths and file sizes? Regardless, I believe Rudegar has already provided you with an answer based on what little you have given us requirements-wise.