I forgot to mention that I'm using esp32 by Espressif System library, the version I'm using is 3.0.3

I found that https://github.com/govorox/SSLClient is based on Based on Mbed-TLS/mbedtls.
Mbed TLS 3.x TLS Versions Supported: Mbed TLS 3.x supports TLS 1.2 and TLS 1.3.
But, I have not found how to hard code the library to use TLS 1.3.

I'm still getting TLS 1.2 when making get request to www.howsmyssl.com.

Making GET request...
Status code: 200
Response: {"given_cipher_suites":["TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384","TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384","TLS_ECDHE_ECDSA_WITH_AES_256_CCM","TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384","TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384","TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA","TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA","TLS_ECDHE_ECDSA_WITH_AES_256_CCM_8","TLS_ECDHE_ECDSA_WITH_CAMELLIA_256_GCM_SHA384","TLS_ECDHE_RSA_WITH_CAMELLIA_256_GCM_SHA384","TLS_ECDHE_ECDSA_WITH_CAMELLIA_256_CBC_SHA384","TLS_ECDHE_RSA_WITH_CAMELLIA_256_CBC_SHA384","TLS_ECDHE_ECDSA_WITH_ARIA_256_GCM_SHA384","TLS_ECDHE_RSA_WITH_ARIA_256_GCM_SHA384","TLS_ECDHE_ECDSA_WITH_ARIA_256_CBC_SHA384","TLS_ECDHE_RSA_WITH_ARIA_256_CBC_SHA384","TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256","TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256","TLS_ECDHE_ECDSA_WITH_AES_128_CCM","TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256","TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256","TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA","TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA","TLS_ECDHE_ECDSA_WITH_AES_128_CCM_8","TLS_ECDHE_ECDSA_WITH_CAMELLIA_128_GCM_SHA256","TLS_ECDHE_RSA_WITH_CAMELLIA_128_GCM_SHA256","TLS_ECDHE_ECDSA_WITH_CAMELLIA_128_CBC_SHA256","TLS_ECDHE_RSA_WITH_CAMELLIA_128_CBC_SHA256","TLS_ECDHE_ECDSA_WITH_ARIA_128_GCM_SHA256","TLS_ECDHE_RSA_WITH_ARIA_128_GCM_SHA256","TLS_ECDHE_ECDSA_WITH_ARIA_128_CBC_SHA256","TLS_ECDHE_RSA_WITH_ARIA_128_CBC_SHA256","TLS_RSA_WITH_AES_256_GCM_SHA384","TLS_RSA_WITH_AES_256_CCM","TLS_RSA_WITH_AES_256_CBC_SHA256","TLS_RSA_WITH_AES_256_CBC_SHA","TLS_ECDH_RSA_WITH_AES_256_GCM_SHA384","TLS_ECDH_RSA_WITH_AES_256_CBC_SHA384","TLS_ECDH_RSA_WITH_AES_256_CBC_SHA","TLS_ECDH_ECDSA_WITH_AES_256_GCM_SHA384","TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA384","TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA","TLS_RSA_WITH_AES_256_CCM_8","TLS_RSA_WITH_CAMELLIA_256_GCM_SHA384","TLS_RSA_WITH_CAMELLIA_256_CBC_SHA256","TLS_RSA_WITH_CAMELLIA_256_CBC_SHA","TLS_ECDH_RSA_WITH_CAMELLIA_256_GCM_SHA384","TLS_ECDH_RSA_WITH_CAMELLIA_256_CBC_SHA384","TLS_ECDH_ECDSA_WITH_CAMELLIA_256_GCM_SHA384","TLS_ECDH_ECDSA_WITH_CAMELLIA_256_CBC_SHA384","TLS_ECDH_ECDSA_WITH_ARIA_256_GCM_SHA384","TLS_ECDH_RSA_WITH_ARIA_256_GCM_SHA384","TLS_RSA_WITH_ARIA_256_GCM_SHA384","TLS_ECDH_ECDSA_WITH_ARIA_256_CBC_SHA384","TLS_ECDH_RSA_WITH_ARIA_256_CBC_SHA384","TLS_RSA_WITH_ARIA_256_CBC_SHA384","TLS_RSA_WITH_AES_128_GCM_SHA256","TLS_RSA_WITH_AES_128_CCM","TLS_RSA_WITH_AES_128_CBC_SHA256","TLS_RSA_WITH_AES_128_CBC_SHA","TLS_ECDH_RSA_WITH_AES_128_GCM_SHA256","TLS_ECDH_RSA_WITH_AES_128_CBC_SHA256","TLS_ECDH_RSA_WITH_AES_128_CBC_SHA","TLS_ECDH_ECDSA_WITH_AES_128_GCM_SHA256","TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA256","TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA","TLS_RSA_WITH_AES_128_CCM_8","TLS_RSA_WITH_CAMELLIA_128_GCM_SHA256","TLS_RSA_WITH_CAMELLIA_128_CBC_SHA256","TLS_RSA_WITH_CAMELLIA_128_CBC_SHA","TLS_ECDH_RSA_WITH_CAMELLIA_128_GCM_SHA256","TLS_ECDH_RSA_WITH_CAMELLIA_128_CBC_SHA256","TLS_ECDH_ECDSA_WITH_CAMELLIA_128_GCM_SHA256","TLS_ECDH_ECDSA_WITH_CAMELLIA_128_CBC_SHA256","TLS_ECDH_ECDSA_WITH_ARIA_128_GCM_SHA256","TLS_ECDH_RSA_WITH_ARIA_128_GCM_SHA256","TLS_RSA_WITH_ARIA_128_GCM_SHA256","TLS_ECDH_ECDSA_WITH_ARIA_128_CBC_SHA256","TLS_ECDH_RSA_WITH_ARIA_128_CBC_SHA256","TLS_RSA_WITH_ARIA_128_CBC_SHA256","TLS_EMPTY_RENEGOTIATION_INFO_SCSV"],"ephemeral_keys_supported":true,"session_ticket_supported":true,"tls_compression_supported":false,"unknown_cipher_suite_supported":false,"beast_vuln":false,"able_to_detect_n_minus_one_splitting":false,"insecure_cipher_suites":{},"tls_version":"TLS 1.2","rating":"Probably Okay"}

I'm now using the GovoroxSSLClient (v 1.3.2), the ESP32 by Espressif Systems (v 3.0.3), the ArduinoHTTPClient (v 0.6.1) libraries.
I'm getting:

Making POST request...
Status code: -3
Response:

Here is my code:
#include <ArduinoHttpClient.h>
#include "WiFi.h"
#include "SSLClient.h"

#include "ca_cert.h" // Include the header file with the certificate

// Replace these with your Wi-Fi credentials
const char* ssid = "YOUR SSID";
const char* pass = "YOUR PASSWORD";

// Update with your endpoint hostname
const char hostname[] = "https://apex.oracle.com/";
const char endPointURL[] = "/wkspace/insert_data";
int port = 443;

// Layers stack
WiFiClient wifi_transport_layer;
SSLClient secure_presentation_layer(&wifi_transport_layer);
HttpClient http_client = HttpClient(secure_presentation_layer, hostname, port);

void setup() {
Serial.begin(115200);

// Connect to Wi-Fi
WiFi.begin(ssid, pass);
Serial.print("Connecting to Wi-Fi");
while (WiFi.status() != WL_CONNECTED) {
Serial.print(".");
delay(300);
}
Serial.println();
Serial.print("Connected with IP: ");
Serial.println(WiFi.localIP());

// Add CA Certificate
secure_presentation_layer.setCACert(root_ca);
}

void loop() {
Serial.println("Making POST request...");

// Prepare POST request payload
String payload = "sensor_value=4.5"; // Example payload

// Set request headers and payload
http_client.beginRequest();
http_client.post(endPointURL);
http_client.sendHeader("Content-Type", "application/x-www-form-urlencoded");
http_client.sendHeader("Content-Length", payload.length());
http_client.sendHeader("Connection", "close");
http_client.endRequest();

// Send payload
http_client.print(payload);

// Read response
int status_code = http_client.responseStatusCode();
String response = http_client.responseBody();

Serial.print("Status code: ");
Serial.println(status_code);
Serial.print("Response: ");
Serial.println(response);

http_client.stop();

delay(30000);
}

Now I have a successful POST request.
The issue with the previous code was:

Ensure that the hostname is correctly set and does not include the protocol (https://). The hostname should only be the domain part of the URL.

The endPointURL should be the path part of the URL, without the leading /. In this case, it's correct.