Here is the best setup (I think so :D) for K-series Keychron keyboards on Linux.
Note: K-Pro and Q-Pro series keyboards use QMK as firmware and most tips here do not apply to them. Maybe the ones related to Bluetooth can be useful, but everything else, especially stuff related to Apple's keyboard module on Linux, likely won't work.
Most of these commands have been tested on Ubuntu 20.04 and should also work on most Debian-based distributions. If a command happens not to work for you, take a look in the comment section.
Keychron Keyboards on Linux use the hid_apple
driver (even in Windows/Android mode), both in Bluetooth and Wired modes.