AlphaClock is the sort form of “alphanumeric clock” as the displays used can also show text.
One advantage of the Arduino Micro ist that it can be plugged in directly to a breadboard and has a micro USB connector for data transfer and power supply. However from LCD2USB I also know the ATmega in a DIP package. For normal operation with external clock this controller only needs a crystal and two capacitors.
My idea was to combine an ATmega328P with two DL-2416 from 1987 and a DS3231 realtime clock module. The whole thing was also a project to learn to know the development environment as Visual Studio Code and PlatformIO as well as the way how the microcontroller works in terms of interrupt control and PWM.