Keychron K2 configuration on Linux
Function keys do not work
To make the change permanent, Kernel_modules#Setting_module_options the hid_apple fnmode option to 2:
/etc/modprobe.d/hid_apple.conf
options hid_apple fnmode=2
Switching Cmd and Alt/AltGr
This will switch the left Alt and Cmd key as well as the right Alt/AltGr and Cmd key.
Permanent change, taking place at next reboot:
/etc/modprobe.d/hid_apple.conf
options hid_apple swap_opt_cmd=1
You then need to regenerate the initramfs.