Ios sends a message why 5g is not displayed.

Ios says it doesn't display 5g because

There are generally two reasons for using a 5G mobile phone but not displaying a 5G network. First, because the current location is not within the coverage of 5G signals, even if using 5G mobile phones and 5G mobile phone cards, mobile phones will still display 4G networks; Second, the 5G network switch of the mobile phone may not be turned on.