Why is CoAP latency higher? (CoAP vs MQTT)

[Fjoaoo]

I've been testing the CoAP client through the libcoap library with confirmable messages. I noticed that there is an average latency of 4.5 ms for sending processing and an average of 15 ms for confirming.

And this left me in doubt, theoretically CoAP should be faster, however, in MQTT using the Arduino framework and the PubSubClient library to publish on a broker, receive on a device with QoS 1 and confirming the message, all this takes on average 6 to 7 ms of latency...

All tests were done more than once on a local network and with a 1024-byte message. I'm really new to this platform, I'd like to know your opinions, if I'm doing something wrong or is it just like that.

I used TLS.

I used the ESP-IDF example and just modified the base settings and the line:

coap_add_data_large_request(session, request, 1024, data, NULL, NULL);