We use the sorting algorithm provided by Chromium’s implementation of the web standard https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/Collator/compare
This is a native method that’s optimized to run fast. Anything else (or custom implemented) is at least 10x slower and will make the file explorer lag the entire app.
I believe this takes into account the “system default locale” your OS is set to, but failing that we have no control over the internal implementations on how names are sorted.
Since you said it’s a double byte, then it’s highly likely this is just a limitation of the js engine, so there’s really not much we can do - I suspect any web-powered app will have the same issue and it’s something beyond our control.