This guide explains the whole process to root Creality K1 and K1 Max and add good stuffs to your printer.
The advantage is to have full access to the firmware and configuration files in order to be able to make changes to them.
If you don't know what you're doing, I don't recommend following this guide.
Note: Some of the firmwares were provided by Creality but have not yet been released publicly.
Guide is available here: Wiki
Credits are available here: Special Thanks