This is big news. I have periodically tried it ever since it was released and not once have I gotten it to work. Until now.
I am on a Mexican vacation with my family and both of my tween kids have Apple Watches. We gave them free run of the resort but wanted to get a hold of them easily. I figured what the hell, let’s try walkie talkie again. AND BY GOLY IT WORKED on my series 7 and my wife and daughters SEs. It wasn’t perfect — especially at the beach where WiFi was spotty — but around the resort itself it worked perfectly. If we could hear it. I don’t believe there are any haptics when you get a message. But otherwise it finally worked!
Toggle FaceTime audio on the watch.
Cannot find the option to enable Facetime on watch. I have looked in general settings and in various watch app or notification settings for phone, messages, notifications, etc. Do you recall where you set this?
Google is your friend:
If you’re unable to make FaceTime calls on your Apple Watch, go to iPhone Settings > FaceTime and if you see Use your Apple ID for FaceTime, tap it. Once you have enabled FaceTime via your Apple ID, restart both iPhone and Apple Watch. After this, the calls should not fail.
https://www.idownloadblog.com/2022/01/21/how-to-fix-facetime-not-working-apple-watch/