I had a similar issue with mine. But was able to reset it with Fn + z + j for a couple of seconds.

Yeah on the mac it works fine. The keyboard just shipped with the Left Alt and Left Windows key in the correct positions, but they are mapped opposite in the firmware. Imagine how maddening it was in the beginning.

> "the little switch on the side of mine that toggles between Mac and Windows"

The physical slide switch on the Keychrons is a net negative for power users who use a KVM between Windows/Mac/Linux because it would wear out quickly and isn't replaceable. It's more sensible to have switching between layouts by keypress combination.