Sending configuration data as string to custom Zigbee STM32

Hi all,
I’ve created a custom LED driver based on STM32 microcontroller. I control a few PWM channels from React App. For my backend I am using Node JS, Express, MongoDB. I can change some settings and save them on the mc’s flash memory:

typedef struct {
	uint8_t  PWM_CHANNELS;
	bool Pwm_RTC_en[6];
	uint16_t pwm_brightness[PWM_CHANNELS_MAX][24];
    float CurrentSenseFactor;
    float TemperatureOffset;
} SystemSettings_t;

What I’m trying to do is to serialize that data, and send it to the MCU. For now, I am stuck at sending any string to the MCU. Is there a converter that I could use for that? Do I even need a converter? STM32 uses ZCL, and I think I need to create a custom cluste. Would you please point me in the right direction?

Thank you,