I am using Preferences.h to store data on my M5 Stack Paper, such as Wi-Fi credentials, during my application's setup. It was working fine.
During development and testing, I have rewritten the data in Preferences multiple times on this device. However, I recently noticed that new data is no longer being stored in Preferences, even though there is still available space, as confirmed by running the following code.

#include <Preferences.h>
.
.
.

void checkWifiCredentialsAndDecide(){
  preferences.begin("wifiCredentials", false);

 if(debugFlag){
    size_t whatsLeft = preferences.freeEntries();   
    Serial.printf("Available enteries in the namespace table.\n" );
    Serial.println(whatsLeft);
    preferences.putString("test1", "test 1 value"); 
    Serial.println("preferences.getString(test1): " + String(preferences.getString("test1", "Default value")));
 }
.
.
.
}

Output

Available enteries in the namespace table.
127
preferences.getString(test1): Default value // I am expecting to see "test 1 value"

I have read that the NVS (Non-Volatile Storage) has a write cycle limitation of approximately 10,000 to 100,000 cycles.
I have a few questions:
Is there a way to check how many write cycles are remaining?
Can I check if my flash memory is healthy or corrupted?
Is it possible that the flash memory of my M5 Stack Paper has worn out?

Thank you