In addition to the automatic network search, the LG unit can also select the network manually, and once the network has been selected manually, it will not switch to another network if reception is also lost.

Depending on the environment and model, the network search can take a long time.

Android 9 | LG UX 9.0
Step 1:  Open the  Settings
Step 2:  Tap on  Mobile networks
Step 3:  Tap on  Network operators
Step 4:  Tap on  Search networks
  1. Open the Settings
  2. Tap on Mobile networks
  3. Tap on Network operators
  4. Tap on Search networks

LG Instructions