Back to our previously scheduled program...
I purchased my 2020 Giant Phantom the first week of March, just a week ahead of things starting to tighten up due to Covid.  I knew that battery life was dependant on a whole host of variables: battery size, style of riding, terrain and assist level.  One of the reasons I favoured a Giant was that with the app you can adjust the assist levels.
My rides are primarily 90% paved and 10% well packed tails and logging roads. 
Just guessing on my use of the assist levels would be:
Eco          80%
Eco +       10%
Normal     5%
Sport         3%
Sport +      2%
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The first month I rode with the factory settings:
Eco  -      100%
Eco +     175%
Normal   250%
Sport      300%
Sport +   360%
Keeping my battery charged between 80% and 20% I was getting approximately 0.6km per % of battery.  But I was unsure what the rate of battery use was at the top and bottom of the battery.  So I charged the battery to 100% and drained it to 0%.  (of course I hit 0% at the bottom of the steepest and longest hill in town.  But it was a sacrifice for science). Riding my normal range of routes I achieved 51.7km.  That was alright but a bit disappointing.
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This month I amended the assist levels to:
Eco  -        75%
Eco +      125%
Normal   200%
Sport       250%
Sport +   360%
I charged the battery to 100% again and then ran my test.  This time I drained the battery from 100 to 7% and completed 98.4km.  Boy, what a difference.
I think I have found my sweet spot and don't think I need to tweak the settings any further.
Your mileage my vary!