How to delete mavlink command?

I want to transmit mavlink via telem1 on pixhawk with wifi at a high frequency.
But the baudrate of the port is limited.
I want to delete some command in mavlink and all I wanted is only the imu,GPS,attitude,compass information.
On nuttx there is a command “mavlink” that can set the baudrate of telem1.

But how to increase the frequency (default is 80hz around for attitude , not enough) via mavlink?
What’s more, how to delete other mavlink command? Can this be done on nuttx via command “mavlink”?

Is there any document about “mavlink" command on nuttx (pixhawk)?