Change server header on all endpoints (Flask + Nginx + Gunicorn)

Question

I'm working on a Flask app that uses gunicorn and nginx and should hide its server header, so I managed to do it only for the homepage, like this:

gunicorn.conf.py

import gunicorn
gunicorn.SERVER = '.'

nginx.conf

events {
    worker_connections  1024;
}
http{
include /etc/nginx/mime.types;
# include /etc/nginx/conf.d/*.conf;

server{

    #server_tokens off;
    proxy_pass_header Server; # get server from gunicorn



    # let the browsers know that we only accept HTTPS
    add_header Strict-Transport-Security max-age=2592000;

    listen 80;

    add_header Content-Security-Policy $CSPheader;
    gzip on;



    location / {

        proxy_pass  http://127.0.0.1:5000
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-Proto $scheme;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

        client_max_body_size 5M;

    }

    location /static/ {

        alias /home/app/static/;
        proxy_set_header Cookie $http_cookie;

        add_header X-Content-Type-Options nosniff;


    }

}

}

So, in my "/" page I'm getting

But elsewhere I'm displaying my server:

I'm not sure about how communication between nginx and gunicorn works, but I seem to be having a similar problem to this post, but I'm not sure how to use this information.

Any help to actually hide my server header would be really appreciated. Thanks!