Flask - Nginx and Gunicorn in Ubuntu 22.04

With an ubuntu 22.04 at zero I have followed the following process:

sudo apt install python3-pip python3-venv
sudo apt install nginx supervisor
sudo mkdir -p /var/www/myapp
cd /var/www/myapp
python -m venv myenv
source myenv/bin/activate
pip install flask gunicorn
nano myapp.py

I run app and in another console I run

curl http://127.0.0.1:5000/

and the index.html that I have appears correctly.
Now I go to the part to go from a browser

nano wsgi.py

# import myapp Flask application
from myapp import app
if __name__ == "__main__":
app.run(debug=True)

gunicorn -w 4 --bind 0.0.0.0:8000 wsgi:app

It seems that it runs fine, although actually after I go to the browser and it says that there is nothing

Am I doing something wrong in the process?

It seems that deleting cache and others has worked, it was not a matter of code or process.
Greetings,