The data usage is always reset to 0 MB on the LG device on the set reset day of the usage cycle. In addition to changing the reset day, the data usage, i.e. the statistics, can also be manually reset or deleted.

Android 9 | LG UX 9.0
Step 1:  Open the  Settings
Step 2:  Tap on  Mobile data
Step 3:  Open the  Menu
Step 4:  Tap on  Reset data usage
Step 5:  Confirm with  Yes
  1. Open the Settings
  2. Tap on Mobile data
  3. Open the Menu
  4. Tap on Reset data usage
  5. Confirm with Yes

LG Instructions