My iPhone 12 suddenly can't find Home WiFi Network... but all other devices are connected.

I kept getting these "Cellular Service is On or Off" popups with certain apps for last couple days and couldn't figure out why it was happening. Cellular was on and working. But today I just realized that it was not connected to the home wifi network even though it looked/seemed connected. My iMac and other devices are still connected after AT&T had to upgrade/replace their modem/router and to which I have an Eero mesh system throughout the house, so it is very strange that only my iPhone is not connected and it can't find the same wifi network now, nor through "Other Network" login. Under Settings > Wi-Fi > Networks, it searches and doesn't find anything. And yet it shows up on iMac right next to it.

So how do I connect/find wifi network if it's not showing up or can't be manually logged in?