A 16MHz small SRAM Arduino will struggle to do sophisticated graphics. A RaspberryPi might make more sense for that. But have a look at this Awind Thread (I have not tried it myself).
An Arduino is good for controlling stepper motors.
The best Arduino to start with is the Uno because most of the software and add-ons work with it.
You can easily use an Arduino in conjunction with an RPi.
...R
Stepper Motor Basics
Simple Stepper Code
Python - Arduino demo