K0 Max

An option is to compile the keyboard firmware from source code. See, e.g., this for details (just the setup and compile part): How to add different RGB colors to specific layers on the Keychron K0 Max [Tutorial]. For a K0 Max. References K0 Max default keymap K0 Max source code. Note that the base i

You can increase the number of macros and the space for macros, but it requires changing the keyboard firmware (changing a few numbers in the source code and compile). It also opens for defining classic QMK macros (static macros). For example, stable and tested dynamic macros can be migrated to be c

Note that Keychron's firmware now forces (full) NKRO, so it isn't suitable for BIOS use (it would be required to revert to a previous version of the source code and recompiling). It causes problem for some KVMs as well. An example would be K0 Max. It isn't cheap, either. References K0 Max default ke

Re "the Keychron K0 Max isn't available as a keyboard through QMK": The source code is in a fork, not in the main QMK project. And not in the default branch. The setup part (after the prerequisites) can be done in a single step, using a few parameters for 'qmk setup' (Git and/or Make gyrations are c

It is an omission on Keychron's part. It should be relatively easy to add it. I have outlined it in that comment. That was for a K0 Max, but I don't think it would be much different for Q0 Max. Probably, it is just adding a single line in file config.h: #define BAT_LEVEL_LED_LIST { 19, 20, 21, 15, 16,

The keycode is BAT_LVL, a custom (Keychron) keycode that is represented as "CUSTOM(14)" in Via's 'Any', "Battery Level" in "KEYMAP" → "CUSTOM", and "Batt" in the display. The number, 14, may depend on the firmware version (and cause the shift of two) and the specific keyboard. In the Via clone, 'Any

Re "I can't find the JSON file of the K0": K0 Max, presumably. Yeah, both the firmware and JSON files are absent from this page where it is reasonably expected to be (K1 Max, K2 Max, K3 Max, K4 Max, K5 Max, K7 Max, K8 Max, K9 Max, K10 Max, K11 Max, K13 Max, K15 Max, and K17 Max are all there).