It is true though that in terms of laptops my only experience to compare it with was with intel chips, but that's because it used to be hard to find an AMD laptop back then.
Also a Windows machine with WSL isn't the worst thing, just treat it well.
The test itself is simple: a Puppeteer script that loads the Reddit front page and scrolls it at 50 px/s for 10 minutes, in a loop until the battery dies. This actually produces a fairly decent load including video decoding (because Reddit autoplays by default, and there are plenty videos in the feed). I also had Thunderbird, Discord, and Telegram running in the background.
On Windows 11, the battery dies in 500 minutes.
On Linux Mint 21.3, it dies in 200 minutes.
Now, this is because Chrome (and Firefox!) disable GPU-accelerated rendering by default on Linux due to "unstable drivers". To be fair, it really is unstable - when I enabled it and watched the test as it was going, I saw the Firefox tab in a crashed state more than once. But even then, with Firefox + GPU acceleration, I got 470 minutes of battery life on Windows vs 340 minutes on Linux.
It’s bigger problem was it was far too eager to trigger the dGPU, especially with accelerated graphics in browsers and the like. So I ended up running it in integrated only mode, unless I wanted to play games.
AMD did catch up quickly, it's too bad they had to solder RAM to match but it is what it is...