Open the phone dialer.
Yo have seen menu
You’ll get all the information related to your network and you can manually change the network modes, toggle VoLTE, WiFi calling, etc. You’ll have lots to explore.
The WiFi Information provides information about WiFi API, WiFi config and WiFi status.
Sometimes, when 3g/4g signal strength is weak in your area, your phone may switch to 2g. If you want to force your phone to accept 3g/4g signal, you can go to phone testing > phone information, and select WCDMA only ( if you want only 3g) or LTE only (if you only want 4g).