The Sonix QMK community has ported many Sonix MCU boards from the like of womier, redragon and keychron to the open source keyboard firmware QMK.
If you have an older K series Keychron keyboard that includes a Sonix MCU you can flash to a custom firmware that supports QMK/VIA so you dont have to use the garbage stock software.
Though is is worth mentioning that currently there is no support (on main) for Bluetooth. So if you flash your older K series board, you will have to use it wired only.
I understand there is active work on getting Bluetooth working too, but it's nowhere ready to "ship" yet