If you're not aware, you can remap modifier keys in System Settings on macOS. It doesn't have individual settings for left/right versions of a modifier key, so keep it in whichever mode has the modifiers on left/right paired with each other correctly, and then swap their functions to the right ones.
I do, but when on the windows mode the keys mentioned are in the wrong positions.
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Edit and if i switch to the macOS mode. The right alt-gr key is not mapped correctly.
If you're not aware, you can remap modifier keys in System Settings on macOS. It doesn't have individual settings for left/right versions of a modifier key, so keep it in whichever mode has the modifiers on left/right paired with each other correctly, and then swap their functions to the right ones.
https://i.imgur.com/FXkmZRV.png
Settings are per keyboard so fixing your external keyboard won't mix up any other keyboards you use (particularly for laptops).
On macOS:
I use my Keychron C3 in Windows mode because the macOS mode ain't right with the bottom left corner keys.
Maybe placement of Control/Option/Command aren't similar enough to the MacBook Pro keyboard for me.
Been meaning to figure this out and fix it... swapping physical keycaps or remapping in software or replacing the keyboard...
Waiting for it to die and will not buy another of theirs. Piece of shit.
Aw I like mine! Besides those few keys of layout.
Hope your next buy's perfect.