Least to most "destructive" things to test:
• Pull down to refresh inside the Google Home app home screen.
• Try to power cycle at least the main/ master puck.
• Try to disable then enable Nest Wifi Cloud Services from the Google Home app. Wi-Fi (icon) -> Settings (icon) -> Privacy settings -> Nest Wifi Cloud Services.
• Try to disable IPv6. Wi-Fi (icon) -> Settings (icon) -> Advanced networking -> IPv6.
Other relevant things to check:
• While using the Google Home app for Nest Wifi, make sure you don't have any VPN services connected. This includes "Apple iCloud Private Relay" ( https://support.apple.com/en-us/HT212614 ).
• If on iPhone, make sure the Google Home app has been granted permission for "local network support" ( https://support.google.com/chromecast/answer/7172427?hl=en ).
• Make sure you don't run double NAT: Any router in front of Nest Wifi should be in bridge mode, as Nest Wifi itself is a router with NAT, firewall and DHCP.
I've been having a similar issue with Google Router and mesh system. When I talked to support, they made me configure IP passthrough and nothing seems to be working. Internet connection stays on and everything appears to be working for about 30 mins and then it just drops and never picks back up. I would have to restart the router manually. I even ordered a new router thinking it's the router that's gone bad. Me and my wife work from home and this has been very annoying for the last couple weeks. Been using google router for 2 years now and never had such a bad experience.