Drivers and "other stuff" have more impact than the OS itself. I would expect if you installed Windows 11 from a USB stick onto this device that it probably puts performance into "balanced" mode for example, fires up antivirus/malware protection, runs a bunch of esoteric services, throws in a WHQL (stable but crappy) GPU driver etc.
I think the article would have been fairer and more useful to install Windows, and optimize the life out of it and then compare performance and other factors (e.g. battery, heat, fan noise etc.)