I have turned the alert off, in the settings on two of our phones. Hearing the alert on one phone, is more than enough!
How to turn off the emergency alert off in your phones settings:
Search your settings for ‘emergency alerts and Turn off ‘severe alerts’ and ‘extreme alerts.
You will also not receive an alert if:
Your phone is turned off or in airplane mode
You’re connected to a 2G or 3G network
You’re using Wi-Fi only (so not connected to a network)
Only phones and tablets running iOS 14.5/Android 11 or later will receive the alert!!