ESPAsyncWebServer large arrays

#include <WiFi.h>
#include <AsyncTCP.h>
#include <ESPAsyncWebServer.h>

const char *ssid = "";
const char *password = "";
int counter_wifi = 0;
AsyncWebServer server(80);

const uint16_t SAMPLESPERSEND = 512;
const uint8_t SAMPLESSEND = 16; // 512*16 = 8196
const uint8_t SAMPLESNUMSIZE = 8; // as your nums are 0.271184 so 8 chars

float myMeasureVals [SAMPLESPERSEND * SAMPLESSEND];
char myValueArray[SAMPLESPERSEND * (SAMPLESNUMSIZE + 1) + 2 + 1] = {'\0'};
char numBufferArray[SAMPLESNUMSIZE + 1] = {'\0'}; // Converter helper array

void setup() {
  Serial.begin(500000);
  Serial.println();
  Serial.println();
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED)
  {
    delay(500);
    Serial.print(".");
    counter_wifi++;
    if (counter_wifi >= 10) { //after 5 seconds timeout - reset board (on unsucessful connection)
      ESP.restart();
    }
  }
  Serial.println("WiFi connected.");
  Serial.println("IP Address: ");
  Serial.println(WiFi.localIP());


  server.on("/array", HTTP_GET, [](AsyncWebServerRequest * request) {

    for (uint8_t j = 0; j < SAMPLESSEND; j++) {
      if (j == 0) strcat (myValueArray, "[");
      for (uint16_t i = 0; i < SAMPLESPERSEND; i++) {
        // float myTempValue = function2GetValues(); // direct froma function
        float myTempValue = myMeasureVals [i * j];
        // dtostrf(floatvar, StringLengthIncDecimalPoint, numVarsAfterDecimal, charbuf);
        dtostrf(myTempValue, 2, 6, numBufferArray);
        strcat (myValueArray, numBufferArray);
        strcat (myValueArray, ",");
      }
      if (j == SAMPLESSEND - 1) myValueArray [strlen(myValueArray) - 1] = ']'; // overwrite the last ',' with ']'
      Serial.println(myValueArray);
      request->send(myValueArray);
      myValueArray[0] = '\0';  // empty array for next part
    }

  });

  DefaultHeaders::Instance().addHeader("Access-Control-Allow-Origin", "*");
  server.begin();

}

void loop() {

}