There is a workaround for that which I just discovered. If you have Outlook, this app can sync your G-Suite with your non-G-Suite.
I don't think you can add via voice, but it'll at least tell you what's happening
No, they're two separate services and neither are going to do it. You can add your Google Calendar to Outlook.com and vice versa but it isn't editable. Otherwise you can use: