BRD_SBUS_OUT not supported using a serial port for SBus out?

Hi. Using a Matek H743-SLIM

Using a serial port for SBus out. I would like to run @ faster than 50Hz - but I guess brd_sbus_out is only available on boards with a dedicated SBus out port?

Is there any way of increasing the SBus frequency when using a serial port?

servo_sbus_rate does not change the serial port Sbus frequency - I would guess it should? Is this a bug?