Changing Arduino Zero PWM Frequency

Sometimes some fresh air helps...
After a short break I found some copy paste errors and got it up working.
To be able to control the pwm on both pins separately, I changed D3 to TCC1 CBB1 and now I am able to do what I wanted.

Here is my now working code:

void setup()
{
  pinMode(13,INPUT);

  REG_GCLK_GENDIV = GCLK_GENDIV_DIV(1) |          // Divide the 48MHz clock source by divisor 1: 48MHz
                    GCLK_GENDIV_ID(4);            // Select Generic Clock (GCLK) 4
  while (GCLK->STATUS.bit.SYNCBUSY);              // Wait for synchronization

  REG_GCLK_GENCTRL = GCLK_GENCTRL_IDC |           // Set the duty cycle to 50/50 HIGH/LOW
                     GCLK_GENCTRL_GENEN |         // Enable GCLK4
                     GCLK_GENCTRL_SRC_DFLL48M |   // Set the 48MHz clock source
                     GCLK_GENCTRL_ID(4);          // Select GCLK4
  while (GCLK->STATUS.bit.SYNCBUSY);              // Wait for synchronization

//Enable port multiplexer
 PORT->Group[g_APinDescription[3].ulPort].PINCFG[g_APinDescription[3].ulPin].bit.PMUXEN = 1;  // D3(PA09)
 PORT->Group[g_APinDescription[5].ulPort].PINCFG[g_APinDescription[5].ulPin].bit.PMUXEN = 1;  // D5(PA15) 
  
  // Connect the TCC0 timer to the port outputs - port pins are paired odd PMUO and even PMUXE
  // F & E specify the timers: TCC0, TCC1 and TCC2
  PORT->Group[g_APinDescription[3].ulPort].PMUX[g_APinDescription[3].ulPin >> 1].reg |= PORT_PMUX_PMUXO_F; // D3
  PORT->Group[g_APinDescription[5].ulPort].PMUX[g_APinDescription[5].ulPin >> 1].reg |= PORT_PMUX_PMUXO_F; // D5
  
  // Feed GCLK4 to TCC0 and TCC1         ??? Is there any way to feed GCLK4 only to TCC0?
  REG_GCLK_CLKCTRL = GCLK_CLKCTRL_CLKEN |         // Enable GCLK4 to TCC0 and TCC1
                     GCLK_CLKCTRL_GEN_GCLK4 |     // Select GCLK4
                     GCLK_CLKCTRL_ID_TCC0_TCC1;   // Feed GCLK4 to TCC0 and TCC1
  while (GCLK->STATUS.bit.SYNCBUSY);              // Wait for synchronization

  // Single slope PWM operation

   REG_TCC0_WAVE |= TCC_WAVE_WAVEGEN_NPWM;
   while (TCC0->SYNCBUSY.bit.WAVE);               // Wait for synchronization
   REG_TCC1_WAVE |= TCC_WAVE_WAVEGEN_NPWM;
   while (TCC0->SYNCBUSY.bit.WAVE);               // Wait for synchronization

  // Each timer counts up to a maximum or TOP value set by the PER register,
  // this determines the frequency of the PWM operation:
  //
  REG_TCC0_PER = 2400;      // Set the frequency of the PWM on TCC0 to
  while(TCC0->SYNCBUSY.bit.PER);

  REG_TCC1_PER = 2400;      // Set the frequency of the PWM on TCC1 to
  while(TCC0->SYNCBUSY.bit.PER);

  // The CCBx register value corresponds to the pulsewidth in microseconds (us)
  REG_TCC0_CCB1 = 1600;       // TCC0 CCB0 - 50% duty cycle on D2
  while(TCC0->SYNCBUSY.bit.CCB1);

  REG_TCC1_CCB1 = 800;       // TCC0 CCB0 - 50% duty cycle on D2
  while(TCC0->SYNCBUSY.bit.CCB1);


  // Divide the 48MHz signal by 1 giving 48MHz
  REG_TCC0_CTRLA |= TCC_CTRLA_PRESCALER_DIV1 |    // Divide GCLK4 by 1
                    TCC_CTRLA_ENABLE;             // Enable the TCC1 output
  while (TCC0->SYNCBUSY.bit.ENABLE);              // Wait for synchronization
  REG_TCC1_CTRLA |= TCC_CTRLA_PRESCALER_DIV1 |    // Divide GCLK4 by 1
                    TCC_CTRLA_ENABLE;             // Enable the TCC1 output
  while (TCC1->SYNCBUSY.bit.ENABLE);              // Wait for synchronization
}

Thank you all again for your provided knowledge! I would not have been able to do this without this topic.