// here I'm getting an http request
String payload = https.getString();

// checking the payload, it seems fine in console but I get some garbage characters when àèéùìò are printed
Serial.println(payload);

// Length (with one extra character for the null terminator)
int str_len = payload.length() + 1;

// Prepare the character array
char xml[str_len];

// Copy it over
payload.toCharArray(xml, str_len);

// there I'll parse xml with tinyxml2 but the MCU crashes before getting here