> ...the next time I book I'll pay cash directly with the host because it will be that much cheaper.

This probably won't work for you. It specifically violates Airbnb's TOS to attempt this, and Airbnb scans all messages between you and the host to ensure that you are not attempting this.

As for arranging it with a F2F conversation with the host, it's been years since I've rented an Airbnb and met a host F2F. That doesn't happen much any more.