We actually do that. We have just released a web widget which maps to your current phone number IVR or voice bot flow. Have put a quick link on our web site at the bottom left corner, not clean ,but works :)

https://ozonetel.com/ind/

I believe in this example, OP is requesting a phone number dedicated to the onair coupling. So the "dedicated" number would serve as a prophylactic managed through onair.

actually I'm curious about how to get a business-related phone number like this? Does Google Voice do this, but also support round-robin, transcriptions, and webhooks?

You don't need a fancy service for this. Every phone operator supports it out of the box.