Bad battery life

I am using an iPhone to pair with the watch. I started from a full charge and estimated 26 days of battery life, with the following settings:

  • activity tracking + move iq
  • no gps
  • no move alert
  • no sleep pulse ox
  • 20% backlight
  • no backlight gesture

I also had good sunlight exposure almost every day. The watch lasted 15 days. I brought the device in my local Garmin shop, but they only reset the settings, which lead to no changes, as the next test with the same settings resulted in 16 days battery life.

Judging by what is supposed to be normal (https://www8.garmin.com/manuals/webhelp/GUID-A298EB1C-21D9-430F-8D06-A2CC74E5D5E9/EN-US/GUID-BCA44331-7CAC-4734-9222-6066B05C32AB.html), I am planning to return it to the shop once again. Does anyone else experience this issue? I am interested in what you guys think.