How to get Airspeed telemetry on Tx and create a stall alarm?

I have a digital airspeed sensor and I see airspeed telemetry on Mission Planner when I have it connected to the plane by USB. But I do not see airspeed listed as one of the telemetry variables being sent to my transmitter (Radiomaster TX16S running latest EdgeTX). Do I need to set something in Ardupilot to receive airspeed telemetry? I am using the Matek F405-VTOL flight controller and Arduplane 4.4.1. Searching for this topic did not turn up any answers yet here, but lots of misuse of the word “airspeed” to refer to transmit baud rates.

I would like to create a stall alarm that plays a sound on my Tx when the airspeed is below some threshold where a stall is imminent.