The date is determined on the LG device by the network. This is done automatically, although the date can also be changed manually. Before doing so, the automatic function must be deactivated.

Android 9 | LG UX 9.0
Step 1:  Open the  Settings
Step 2:  Tap on  General
Step 3:  Tap on  Date & time
Step 4:  Disable  Set automatically
Step 5:  Tap on  Set date
Step 6:  Choose desired  Date
Step 7:  Confirm with  OK
  1. Open the Settings
  2. Tap on General
  3. Tap on Date & time
  4. Disable Set automatically
  5. Tap on Set date
  6. Choose desired Date
  7. Confirm with OK

LG Instructions