Thanks for the reply
This is the machine.
https://www.elegoo.com/product/elegoo-uno-r3-2-8-inches-tft-touch-screen/
I received confirmation from Elegoo, that they occupy pin 0 and 1 but they actually don't use them. So there is no problem to use the screen from the Arduino and to communicate concurrently the Arduino with the computer through the USB connection.
This provides a very convenient managed external control interface for many possible uses, at a very reasonable price.
Also, I made a mistake when reading the examples from Elegoo web site. They don't use the Serial instance to communicate with the screen. They make the communication using several parallel digital pins for that purpose.
I still don't have the machine (will arrive to Costa Rica - my country - by sea). But when it arrives, I will provide complete feedback about this.