Electronic to control matrix of electro-devices

For some concept design I would like to control with computer (or processor unit in future), matrix (m,n) of small devices like step motors or elektromagnets. value for each device is of 8bit (0 to 256). Any idea for solutions, development, cost etc. Something like 8bit greyscale image where level of grey is level for each electro-device. Also what is the limit of that matrix for realtime controll.

what is the order of m and n?
what is the current and voltage of one device?
what is real time in your case?

thx for replay....I am designer by profession, and my knowledege of electronics is very limited.

Matrix should be sized at least 25x25, for testing purpose, but I am intested to have option to build big like 100x100 or even mor, depending on possibility.

Voltage depending on the device. I thought to have micro step motors or electromagnets for smooth linear movements.

I would like to have something like this but with diferent movements. View attachment 63741. It should process input from sensors, process, and put in position according to input... it should be almost realtime.. but delay in second is ok.