Multiple Stepper Motor Woes and Confusion

Forgive my lack of knowledge I am very much a noob at this kind of thing.

I'm in the process of creating my first Arduino project, it requires two stepper motors (28BYJ-48's) linked to the arduino using two ULN2003 Driver boards.

These are being powered currently by a Breadboard Power Supply module connected to a 9V battery.

This all seems to work fine with a single stepper but stops with the introduction of the second.
I'm pretty certain from extensive research that this should be possible with the set up I have and that the circuitry is correct (I'm having problems finding an application to draw out the circuit I have that includes these stepper motors and the Driver boards I am using, tinkerCad seems to be lacking in this department, if there is one I am missing, perhaps someone could provide me a link?)

So the first problem is just that, I am unable to get both steppers to work together, and not just vibrate, is this a power issue? or is there something obvious I am missing?

The second issue is related to the code.

//Libraries

#include "Stepper.h"
#include "IRremote.h"

//Variables

#define STEPS  32   
int  Steps2Take;  // 2048 = 1 Revolution
int  Steps2TakeRight;  // 2048 = 1 Revolution
int receiver = 12; // Signal Pin of IR receiver to Arduino Digital Pin 6
boolean walkCycle;

//Objects

Stepper stepperLeft(STEPS, 8, 10, 9, 11);
Stepper stepperRight(STEPS, 4, 6, 5, 7);
IRrecv irrecv(receiver);    // create instance of 'irrecv'
decode_results results;     // create instance of 'decode_results'

void setup()
{ 
  irrecv.enableIRIn(); // Start the receiver
  Serial.begin(9600);
}

void loop()
{
if (irrecv.decode(&results)) // Check for IR signal

  {
    switch(results.value)

    {
      case 0xFFA25D: // POWER Button Pressed
                      if (walkCycle == 0){walkCycle = 1;}
                      else{walkCycle = 0;}
                      
                      Serial.println("POWER");
                      Serial.println(walkCycle);
                      break;
                  
      case 0xFFA857: // VOL+ button pressed
                      stepperLeft.setSpeed(500); 
                      Steps2Take  =  2048;  // Rotate once CW
                      stepperLeft.step(Steps2Take);
                      Serial.println("VOL+");
                      break;

      case 0xFF629D: // VOL- button pressed
                      stepperLeft.setSpeed(500);
                      Steps2Take  =  -2048;  // Rotate once CCW
                      stepperLeft.step(Steps2Take);
                      break;
                
    }
        
      irrecv.resume(); // receive the next value
                 digitalWrite(4, LOW);      
                 digitalWrite(5, LOW);
                 digitalWrite(6, LOW);
                 digitalWrite(7, LOW);    
                 digitalWrite(8, LOW);
                 digitalWrite(9, LOW);
                 digitalWrite(10, LOW);
                 digitalWrite(11, LOW); 
  }  
    if (walkCycle == 1)
      {
                      stepperLeft.setSpeed(500); 
                      stepperRight.setSpeed(500); 
                      Steps2Take  =  -10;  // Rotate CW    <---- Why am I having to make this -ve for CW rotation?
                      Steps2TakeRight  =  10;  // Rotate CCW
                      
                      Serial.println("walkCycle Active");
                      
                      stepperLeft.step(Steps2Take);
                      //stepperRight.step(Steps2TakeRight);
        }

}

In the switch statement, I am able to control the direction of the rotation correctly, with a +ve Steps2Take rotating the motor Clockwise and -ve going Counter Clockwise.

But using the if statement below I have to invert this to get the correct direction, why is this? I know from prior coding experience forcing something to do what you want by hardcoding backward like I have done here is generally a bad idea and can cause issues later, I just wondered if anyone has any suggestions as to why this is.

Finally, the Breadboard power module is clearly not intended for use in the final project, should I be looking into getting a something such as a Adafruit Power Boost Shield for the final project.

IMPMaster:
So the first problem is just that, I am unable to get both steppers to work together, and not just vibrate, is this a power issue? or is there something obvious I am missing?

If both motors work separately a power problem is most likely.

Your description of how the motors are powered is very vague "powered currently by a Breadboard Power Supply module connected to a 9V battery."

If you mean one of the small PP3 style 9v batteries then that is almost certainly the problem.

BUT ...

28BYJ-48 motors usually work with 5v and not 9v so I am not going to advise you to get a bigger 9v battery. If they are 5v motors then for testing they will probably run from a pack of 3 x AA alkaline cells (4.5v).

...R