Hi @benjamin-linne,
Supporting more ESCs in the future is definitely on the roadmap, but no hard timelines to provide.
In general, the current ESC is interfaced with a UART based driver, eg. here:
https://github.com/modalai/px4-firmware/blob/v1.2.x-modalai-rb5-flight-alpha/src/drivers/uart_esc/modalai_esc/modalai_esc_serial.cpp#L50
This UART itself actually resides in the DSP, so it's customizable but we need to get a bit more docs up for this to make it achievable for others!