So... you already owned Google Home minis... why not buy Google's Nest doorbell, which rings every Google Home device out of the box with none of the absurdity? If you have a Google 4k TV Streamer, it even pops up on your TV when someone rings the doorbell...
When I started my search, I thought this £30 doorbell would be good enough and I wouldn't need the £180 Nest doorbell. Little did I know...
Indeed the Nest integration is pretty solid.
That said, the author might also consider installing an actual doorbell, which is a device their home should have had decades ago. You'll also want something to provide power to the Nest, so this is almost free.