Simpler too swap change servo2_pin 5 to 4 and change servo3_pin 4 to 5, thereby swapping servo2 to servo3 and vise versa
#ifdef IS_RAMPS_13
#define SERVO0_PIN 7 // RAMPS_13 // Will conflict with BTN_EN2 on LCD_I2C_VIKI
#else
#define SERVO0_PIN 11
#endif
#define SERVO1_PIN 6
#define SERVO2_PIN 5
#define SERVO3_PIN 4
#ifdef IS_RAMPS_13
#define SERVO0_PIN 7 // RAMPS_13 // Will conflict with BTN_EN2 on LCD_I2C_VIKI
#else
#define SERVO0_PIN 11
#endif
#define SERVO1_PIN 6
#define SERVO2_PIN 5
#define SERVO3_PIN 4