Stepper Motor Angle and Speed Control

I'm not quite shure what you want to do. But to reset your buttonState you could use the MoToTimer class. Every time you set your buttonState you also set the timer to 300ms. And if it expires, you set buttonState back to 0.

...
MoToButtons myButtons( buttonPins, 1, 20, 3000 );   // manage buttons(s), longpress is 3 seconds
MoToTimebase printTimer;                            // Timer to print in regular intervals without blocking sketch
MoToTimer rstButtonTimer;                           // Timer to reset buttonState
...
    myButtons.processButtons();

    if ( rstButtonTimer.expired() ) {
        // Timer expired, reset buttonState
        buttonState = 0;
    }
...
        buttonState = 3;
        rstButtonTimer.setTime(300);
...
        case NOCLICK:
            // leave this empty as it is
            //if ( buttonState > 0 wait reset to 0 every 300ms ? // How do i reset this ir is there an MOBA function to use?
            break;
...
            buttonState = 2;
            rstButtonTimer.setTime(300);
...
            buttonState = 1;
            rstButtonTimer.setTime(300);
...

Of course I could not test, but you can give it a try.