Connecting an external camera to iPhone XI, then using it for Skype and Zoom using a smart TV as a screen
You should be able to do this with the Apple Digital AV Adapter as it allows you to connect an external monitor to your iPhone/iPad device.  That would be the most efficient method.
The second method to do this would be to utilize an AppleTV  connected to the external monitor/TV.  You would then AirPlay the Zoom meeting to AppleTV.  This would meet your requirements of being wireless, but keep in mind that in an office environment where there's lots of demand for WiFi, you may see a choppy video due to network latency and dropped packets.  If possible, create a dedicated VLAN with QoS (quality of service) configured to put priority on that traffic.
A third option would be to simply get an inexpensive Mac like a Mac mini and connect the screen along with a quality webcam like the Logitech Brio or if the room is large enough, one of their &quot;pro grade&quot; conference web cams.