I haven't had to make any changes to my Google Wi-Fi network in years. Today I launched the Google WiFi app on my iPhone and found that it wouldn't do anything with the net and that I had to use Google Home. I downloaded that and told Google WiFi to migrate to Google Home. I brought up Google Home and at first, it identified the point connected to the router and one of the other two points. It lost the name of the wireless network during the migration and none of my devices could see or connect to it. Reading some help articles I pressed the button on each of the points and now Google Home can't see them.
I can attach to any one of the three now with my computers and printers, but not to the named network. Only to an individual point.
Factory reset each point and set them up from scratch in the Google Home app, is the least painful way to get it up and running. Use the same network name (SSID) and password, then all your devices should reconnect automagically.