Thank you, dear reader, for reminding me that the Google Home devices make phone calls. I constantly forget that they can do that! And as a result, I don’t have much experiencing with this myself, except for the hour of Googling I did to try and answer your question. I hope this helps anyone out there using both of the smart assistant platforms in their home. I’ve written about using Alexa and the Google Assistant at the same time before, and while I know it can be a bit fragmented at times, I didn’t expect it would be this limiting.
I’ve personally switched my house over to Google Assistant-enabled devices, though I have an Amazon Echo Dot in the backroom for when I’m comparing answers for common commands. But still, it’s not as set up as the Google-activated accounts, so I’ve never even linked my phone number to Alexa.
I did some digging around, and it looks like your best bet is to sign up the Echo Dot with an alternate mobile number. Google Voice is still doling them out, so maybe it’s time that you’re officially acquainted. Apps like Burner and Sideline also offer monthly phone plans for lines you can use directly from your phone.
If you’d rather use Alexa calling instead of Google’s calling features, try unlinking your phone number through the Google Home app for your smartphone, then signing up for that aforementioned Google Voice number. Once that’s configured, set it up so that Google Voice routes through your Google smart devices, and your usual phone number works through Alexa-enabled devices. It’ll confuse the heck out of everyone in your life when you’re calling them from two different numbers, but at least you’ll be able to make phone calls from both platforms.
Hopefully, I’ve answered your question. Hopefully, this stuff becomes more user-friendly down the line.