iPhone doesn't connect to cellular network
Cell signal is poor in my house so the phone is switched to allow wi-fi calling which works well. The problem occurs when I step out of the door and it does not automatically connect every time to the cell provider's network. Sometimes I can make it connect by toggling airplane mode, other times I have to shut the phone down and reboot it. Why is this? How can correct it? it's an iphone 8 running iOS 16.7.10.
iPhone 8, 16