Many users have posted on this forum on their real world issues of GnuLinux (Or Zorin OS) getting less battery life than Windows did before their switch.
For the last several years, I have been a member of daily troubleshooting here, seeing and trying to help resolve these complaints.
Summary
Improve battery life on Linux (better than TLP)
Increase battery life with TLPUI
While a persons experience may speak louder to themselves than another persons anecdote, to them, your experience is just your anecdote with a statistical validity of One.
This is why anecdote does not equal evidence and why articles, even if you disagree due to them differing from your anecdotal experience, cannot be easily dismissed as mere "opinions" and "claims". That would be "cherry-picking the evidence."
As the article points out, battery life is not a simple thing. Windows OS is provided by Microsoft, a milti-trillion dollar entity that has the resources GnuLinux lacks.
Power management, driver efficiency, and software optimization are the primary things to consider for battery life. Windows has access to Hardware Support that GnuLinux does not. The Manufacturers work with MS closely while ignoring GnuLinux.
Proprietary Software provides the best drivers for Windows. On GnuLinux, drivers are community supported and can be less optimized.
Community support has less access to the proprietary code and at times, must guess as to the appropriate optimizations for driver configuration. It's not so easy.
Windows O.S. is bloated compared to the often far more trim GnuLinux distros, but M.S. has the money and resources to pay into Optimization of Power Management systems. In spite of being a ballooned whale, Windows often shows surprisingly good battery life which customers/consumers demand.
Mileage will vary and I have experienced both personally, with a trend toward better battery life on GnuLinux possibly due to my preferred use of Zorin OS Lite.