Get notified about a call from an application on Apple Watch
Any time I get a call from an application (i.e. NOT a standard phone call), for example Skype, MS Teams, Slack, or EZVIZ (smart doorbell with camera), my iPhone rings as normal (the UI is a bit different from a normal phone call), but my Apple Watch remains silent. I am not expecting to answer that call using the Watch, but I would like to know that there is a call to answer.
I am getting all other notifications - including those from the mentioned apps - with no issues, so this is not a general notifications problem. Just want to know on the Watch that there is somebody calling me.
Apple Watch Series 4

