IMHO - The easiest solution is to not re invent the wheel and just use existing drivers - e.g. Indi Moonlite driver which has a good amount of info, many Arduino ino files that the Indi driver will work with.
A simple Ardiuno Nano and dvr8825 or A498 controller will work fine unless your unit has a lot of torque which is when you need the higher Amps and this,for example, will driver anything you should likely need TB6560 Single 1 Axis Controller Stepper Motor Driver (Google it) and is totally compatible with 5V Arduino boards.
Google Robert Brown's Focuser pro which has Ardiuno code that is compatible with the Indi Moonlite and has a number of driver options
Should you wish to use a wireless connection Wemos D1 mini pro work again with the Moonlite Ardiuno code the only problem being you may have to use a Logic shifter as Wemos uses 3v and a lot of boards use 5v but all you have to do is wire the connections correctly.
The only preference I have is to use Accel Library to drive the controller from within the Arduino code - a well proven Arduino library ,wih (de)acceleration routines
www.airspayce.com/mikem/arduino/AccelStepper/ but thats your choice.
There are masses of Stepper Motor some cheap and limited (but will do the job depending on the load) and lots that are excellent with high spec gearing attached.
Depending on your torque requirement and accuracy you may get away with
www.amazon.co.uk/Geared-Stepper-28BYJ-48...Driver/dp/B00UB31XGQ which even comes with its own driver board.
In a nut shell the world's your oyster
P.S. you could even use a USB driven focuser - search Indi forum to see the item.
Good luck with your build