4WD/4WS robot rover project

Neewbi here. I have trawled a lot of the posts here trying to learn. I need to build a 4WD 4WSteer robot for agricultural use. The area I am unclear on is how I get the relatively simple steering commands from the PX4 to control the 4 drive motors and the 4 steer motors. I know the Ackerman trigonometry in that if I want to get one wheel to turn left 10 degrees I know what I need to do with the other wheels in terms of angle and rotational speed. That’s just math. Can a 4WD/4WS rover be implemented in QGroundControl or do I need a ‘conversion’ Arduino or similar to interpret the PX4 commands into the more complex motor commands (PWM?) that I require. The motors are 12DC brushed for simplicity at this stage.
Thanks in advance for any guidance (excuse the pun)!
Colin

Can anyone help with this in any way at all please? If not then I will need to ditch QGC and look for another solution. Thanks in advance for any input.
Colin