The Raspberry Pi 400 is a powerful single-board computer with a built-in keyboard. Now, Adafruit has developed a Cyberdeck for it that sits above the keyboard. The expansion should be one of the simplest ways to add a small display without hooking the Raspberry Pi 400 to an external monitor.
https://www.notebookcheck.net/The-Raspberry-Pi-400-gets-a-Cyberdeck-with-Adafruit-s-CYBERDECK-Bonnet-display-add-on.529278.0.html