Company owned devices options for system apps My questions regard the possibility to temperate which phone application could be set up while using Google Workspace (or any other MPA). Specifically: can I set up an application to replace the phone system app?
I've read this but does that means that I can't disable the phone system app? Or that the com.android.phone package is the system app.
Another solution would be to get controls over the default apps settings and lock the employee out of these ones. The MPA solution would then be able to enforce the use of another Phone App as being the default system one. I could not find any documentation covering this.
My interpretation of https://support.google.com/a/answer/7292363 is that
com.android.phone is a system app that cannot be disallowed
However you can create a policy which will prevent non-emergency calls:

4.24. System radio management
4.24.5. IT admins can configure whether the device can make outgoing phone calls, excluding emergency calls (see outGoingCallsDisabled).

At which point you can put your own Phone app on the device. Note limitations on Phone apps that developers are bound to.
So presumably the device will still have the Google phone app but that app can only be used to call emergency services.