> download the resulting json and then flash the firmware to your keyboard via sudo-level flashing tool
Several microcontrollers come pre-shipped with MicroPython and an emulated flash drive where you can drop Python code to alter the running main()
I imagine you could easily do the same with keyboards, except the FS throws an error when you're writing invalid JSON and the emulated FS has emulated security properties so only admin users can write to it. No need to sudo, just authorise the permission prompt when you download/copy the new config to the virtual flash drive.
You could add a little hardware button or toggle switch to the board to enable/disable flash drive emulation if you really wanted to be secure. Write your config, unmount, flip toggle switch.
Several microcontrollers come pre-shipped with MicroPython and an emulated flash drive where you can drop Python code to alter the running main()
I imagine you could easily do the same with keyboards, except the FS throws an error when you're writing invalid JSON and the emulated FS has emulated security properties so only admin users can write to it. No need to sudo, just authorise the permission prompt when you download/copy the new config to the virtual flash drive.