Finally I got from Amazon this fast wifi dongle that’s working also with Ubuntu 18.04. The TP-link AC1200(T4UH) doesn’t come up with plug and play functionality but the driver is very easy to install on Ubuntu and Debian distributions. The dongle is based on the RealteK RTL8812AU chipset, and luckily this driver it’s already in the official repository. Launch this command from you terminal to install it:
sudo apt install rtl8812au-dkms
plug in your device and it should be ready to connect to the WIFI!