Make sure you have no VPN enabled/ connected; not any 3rd party product, nor the "Apple iCloud Private Relay".
Make sure the Google Home app has permissions to "local network access".
I have a few other questions; I have a Netgear CM100 cable modem, and Netgear RAX43-100 NAS Nighthawk Router. Can I also use a Nest Wifi Router? Or do I even need a Nest Wifi Router? Can the two work in harmony? I don't want to change all the passwords on all the ancillary wifi equipment. Your suggestions are greatly appreciated.
The main Nest Wifi puck will act as a router with NAT, firewall, DHCP. Having more routers in front or behind it is not recommended as you'll get double NAT. Any router in front should either be removed or bridged.
I would recommend to remove the Nighthawk router from the mix.
To get your wireless devices to connect to Nest Wifi just reuse the network name (SSID) and password, and they should reconnect automagically.