To update notifications for incoming calls, please go to https://manage.yodel.io/profile
All phone numbers in your account that you have access to are listed in these settings. The push notifications are applied for the iOS and desktop app, as well as the browser and SIP phones (Slack is not included in these settings).
If you don't want to get notified of incoming calls for a specific phone number, you can deactivate the notifications.
To notify the user about a call after the call is routed, you also have the option of "voice IVR" under the phone number settings which are independent of your Slack IVR settings.
As soon as a caller mentions a keyword that is linked to a user, only their devices ring (and the devices of other users that are not linked to the keyword will stop ringing).