Arduino UNO R4 Minima - I can send keystrokes, or I can control a stepper motor. But I can't do both things in the same sketch

[MicroBahner]

@CesareBrizio

    stepper.run();
    Serial.println("THAT ONE - You have 10 seconds to change the active window. Keystroke will be sent to the foreground program window.");
    delay(10000);        
    Keyboard.press(KEY_F1);
    delay(100);
    Keyboard.releaseAll();  

There are some other strange usages of AccelStepper methods, but this definitely cannot work. During your long delay() no steps are created, so your stepper does not move. AccelStepper needs a blocking free design.
That's not a problem of AccelStepper.h and Keyboard.h.
Alternatively you could use the MobaTools library, which is able to create the steps even during delay().