arduino + openFrameworks + ledPin as output

Hello, I am working on a project with 3 timers where at where:
1/ 1st timer started- ledPin not light up
2/ 2nd timer started (and 1st timer finished) - ledPin fading in
3/ 3rd timer started (and 2nd timer finished) - ledPin is ON

I am using ofSerial for connecting another sensor with oF, and working perfectly.
My ledPin is lighting up gradually ignoring my code. May I ask if it is my arduino or oF code that is not working please? Or should I not use ofSerial but firmata in the first place?

Arduino code:

  #include <Firmata.h>  
  #include <CapacitiveSensor.h>

byte sensorByte;
int inputPin = 4;
CapacitiveSensor   sensorPin = CapacitiveSensor(inputPin,2);  
int ledPin = 11;
int ledValue;


void setup() {
     sensorPin.set_CS_AutocaL_Millis(0xFFFFFFFF); 
     Serial.begin(9600);
     pinMode(ledPin, OUTPUT);    
}

void loop() {
    sensing();
    byte ledValue;
    
    if(Serial.available()){    
      ledValue = Serial.read();      
      analogWrite(ledPin, ledValue);
      delay(10);
    }
}

long sensing(){
long total1 = sensorPin.capacitiveSensor(10);

sensorByte = map(total1, 0, 170, 0, 255);
sensorByte = constrain(sensorByte,0,255);

Serial.write(sensorByte);

delay(10);    
}

my oF code:

#include "ofApp.h"

//--------------------------------------------------------------
void ofApp::setup()
{

ofSetVerticalSync(true);

ofBackground(34);
ofSetLogLevel(OF_LOG_VERBOSE);

timer1.setup( 5000 ) ; 
timer2.setup( 3000 ) ;  
timer3.setup (9000);


timer1.start( false ) ;

font.loadFont("franklinGothic.otf",20);

ofAddListener( timer1.TIMER_COMPLETE , this, &ofApp::timer1CompleteHandler ) ;
ofAddListener( timer2.TIMER_COMPLETE , this, &ofApp::timer2CompleteHandler ) ;
ofAddListener( timer3.TIMER_COMPLETE , this, &ofApp::timer3CompleteHandler );
ofAddListener( timer1.TIMER_PAUSED , this, &ofApp::timer1PauseHandler ) ;
ofAddListener( timer2.TIMER_PAUSED , this, &ofApp::timer2PauseHandler ) ;
ofAddListener( timer3.TIMER_PAUSED , this, &ofApp::timer3PauseHandler ) ;

ofAddListener( timer1.TIMER_STARTED , this, &ofApp::timer1StartedHandler ) ;
ofAddListener( timer2.TIMER_STARTED , this, &ofApp::timer2StartedHandler ) ;
ofAddListener( timer3.TIMER_STARTED , this, &ofApp::timer3StartedHandler ) ;

serial.listDevices();
vector<ofSerialDeviceInfo> deviceList = serial.getDeviceList();

int baud = 9600;
serial.setup(0, baud);
serial.setup("/dev/tty.usbmodem1421", baud);

music1.loadSound("music1.mp3");
music2.loadSound("music2.mp3");
music1.play();

     }

//--------------------------------------------------------------
void ofApp::update(){

ofSoundUpdate();

timer1.update( ) ;
timer2.update( ) ;
timer3.update();

}

//--------------------------------------------------------------
void ofApp::draw(){
    
ofSetColor(0) ;
if (bSendSerialMessage){
    for (int i = 0; i< 255; i++){
        serial.writeByte(i);
        cout << i << endl;
    }
    
    bSendSerialMessage = false;
}

if (lightUp){
    serial.writeByte(255);
    cout << "lightUp" << endl;
}
lightUp = false;


}


void ofApp::timer1CompleteHandler( int &args )
{

timer2.start(false);
music1.stop();
music2.setVolume(1);
music2.play();

bSendSerialMessage = true;
lightUp = false;

}

void ofApp::timer2CompleteHandler( int &args )
{

timer3.start(false);
int byteIn = serial.readByte();
printf("%d\n",byteIn);

if( byteIn == OF_SERIAL_NO_DATA || byteIn == OF_SERIAL_ERROR){
    
}else{
    mapByteIn = ofMap(byteIn,0,255,0,1);
    printf("%f\n",mapByteIn);
    cout <<  "playMusic" << endl;
    music1.setVolume(MIN(mapByteIn,1));
    music1.play();
}

music2.stop();

bSendSerialMessage = false;
lightUp = true;
}

  void ofApp::timer3CompleteHandler( int &args )
{
timer1.start(false);
music1.setVolume(0.5);
music1.play();
music2.stop();
bSendSerialMessage = false;
lightUp = false;
}


void ofApp::timer1PauseHandler( int &args ) {
cout<<"TIMER1 PAUSED"<<endl;

}
void ofApp::timer2PauseHandler( int &args ) {
cout<<"TIMER2 PAUSED"<<endl;

}
void ofApp::timer3PauseHandler( int &args ) {
cout<<"TIMER3 PAUSED"<<endl;

}

void ofApp::timer1StartedHandler( int &args ) {
cout<<"TIMER1 STARTED"<<endl;
timer2.togglePause();
}
void ofApp::timer2StartedHandler( int &args ) {
cout<<"TIMER2 STARTED"<<endl;
timer1.togglePause();
}
void ofApp::timer3StartedHandler( int &args ) {
cout<<"TIMER2 STARTED"<<endl;
timer1.togglePause();
}
    for (int i = 0; i< 255; i++){
        serial.writeByte(i);
        cout << i << endl;
    }

How long is it going to take to execute this loop?

    if(Serial.available()){    
      ledValue = Serial.read();      
      analogWrite(ledPin, ledValue);
      delay(10);
    }

How long is it going to take to read the 255 bytes that the other code sent?

Which is going to take longer? What is going to happen when the serial buffer on the Arduino fills up?

In my oF code, I have changed it to:

        if (bSendSerialMessage){
            
            if (increment >= 0){
                increment += 10;
                increment = ofClamp(increment, 0,255);
                serial.writeByte(increment);
                cout << "Writing Byte: " << increment << endl;
                ofSetColor(increment,0,0);
                ofEllipse(100,100,100,100);
            }
        }