The atmega328 was a fine option a decade ago, and I still love them, but they aren't what I'd recommend to someone new. The Pi Pico or an ESP32 make more sense in the current day.
This seems like a project that doesn't need super high performance nor tight timing requirements (for anything other than driving displays), so I'd recommend considering Circuitpython or Micropython instead of C++.
Benn Jordan tends to make longer videos, but they are always worthwhile. If he releases a 40 minute video about a topic I don't care about, I'll still jump to watch it because he'll make it interesting, and I'll probably end up caring about it by the end.