Yeah, a Blink chime is definitely a solution. But after feeling like I got a great deal on a cheap doorbell, I didn't want to buy yet another thing from them. I also thought it would have been easy to play audio on the Google home and so I started tinkering and then got carried away.

MQTT was an option, but it actually felt like overkill to add an MQTT server on my VPS than just a tiny Express server. (But who am I to talk about overkill here.)