Use the number your phone reports
Both major phone systems keep a daily screen time average in their settings. Use the weekly average from there, not your guess. Guesses tend to run low, and the gap is usually the unlocks you do not remember: the 40-second checks that add up to an hour.
Then decide what counts. Phone only, or the laptop and the television too? Either is fine. Just know which one you entered, because the lifetime number moves a lot.