String Typewriter will output a string, one character at a time, at a defined time interval. There is no need for this action to extrapolate an alphabet atlas from an image or convert anything at all. You should use String Typewriter to construct the string over time and simply feed that into a GUI Text or UI Text where you have already setup the font.
Blitting in this context is an archaic method used to display text on old consoles like Atari because there were no better methods available like the one we're using here.