Nginx too many redirect when trying to redirect non www to www

I have this nginx configuration

upstream puma_example.it {
  server unix:/home/deploy/apps/example.it/shared/tmp/sockets/example.it-puma.sock fail_timeout=0;
}
server {
  listen 80;
  listen [::]:80;
  server_name example.it www.example.it;
  return 301 https://www.example.it$request_uri;
}

server {
server_name blog.example.com;
return 301 http://www.example.com/blog$request_uri;
}


server {
  listen 443 ssl http2;
  listen [::]:443 ssl http2;
  ssl_certificate /etc/letsencrypt/live/example.it/fullchain.pem;
  ssl_certificate_key /etc/letsencrypt/live/example.it/privkey.pem;
  server_name www.example.it example.it;
  root /home/deploy/apps/example.it/current/public;
  try_files $uri/index.html $uri @puma_example.it;
  return 301 https://www.example.com$request_uri; 

  client_max_body_size 4G;
  keepalive_timeout 10;

  error_page 500 502 504 /500.html;
  error_page 503 @503;

  location @puma_example.it {
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $host;
    proxy_redirect off;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "Upgrade";
    ssi on;
    proxy_set_header X-Forwarded-Proto https;
    proxy_pass http://puma_example.it;
    # limit_req zone=one;
    access_log /home/deploy/apps/example.it/shared/log/nginx.access.log;
    error_log /home/deploy/apps/example.it/shared/log/nginx.error.log;
  }

  location ^~ /images/ {
    expires max;
    add_header Cache-Control public;
  }

  location ~ ^/(assets|packs)/ {
    gzip_static on;
    brotli_static on;
    expires max;
    add_header Cache-Control public;
  }

  location = /50x.html {
    root html;
  }

  location @503 {
    error_page 405 = /system/maintenance.html;
    if (-f $document_root/system/maintenance.html) {
      rewrite ^(.*)$ /system/maintenance.html break;
    }
    rewrite ^(.*)$ /503.html break;
  }

  if ($request_method !~ ^(GET|HEAD|PUT|PATCH|POST|DELETE|OPTIONS)$ ){
    return 405;
  }

  if (-f $document_root/system/maintenance.html) {
    return 503;
  }
}

I'm trying to redirect non www to www and to redirect the third party domain blog to a specific url but I think that adding

return 301 https://www.example.com$request_uri;

in that position it cause a redirect loop. Where do I have to place it? What is wrong in this config?

I try also to separate blocks

upstream puma_example.it {
  server unix:/home/deploy/apps/example.it/shared/tmp/sockets/example.it-puma.sock fail_timeout=0;
}

server {
  listen 80;
  listen [::]:80;
  server_name example.it www.example.it;
  return 301 https://www.example.it$request_uri;
}

server {
  listen 443 ssl http2;
  listen [::]:443 ssl http2;
  ssl_certificate /etc/letsencrypt/live/example.it/fullchain.pem;
  ssl_certificate_key /etc/letsencrypt/live/example.it/privkey.pem;
  server_name example.it;
  return 301 https://www.example.it$request_uri;
}

server {
  listen 443 ssl http2;
  listen [::]:443 ssl http2;
  ssl_certificate /etc/letsencrypt/live/example.it/fullchain.pem;
  ssl_certificate_key /etc/letsencrypt/live/example.it/privkey.pem;
  server_name hinnovation.example.it;
  return 301 https://www.example.it/speciale/innovation$request_uri;
}


server {
  listen 443 ssl http2;
  listen [::]:443 ssl http2;
  ssl_certificate /etc/letsencrypt/live/example.it/fullchain.pem;
  ssl_certificate_key /etc/letsencrypt/live/example.it/privkey.pem;
  server_name www.example.it;
  root /home/deploy/apps/example.it/current/public;
  try_files $uri/index.html $uri @puma_example.it;

  client_max_body_size 4G;
  keepalive_timeout 10;

  error_page 500 502 504 /500.html;
  error_page 503 @503;

  location @puma_example.it {
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $host;
    proxy_redirect off;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "Upgrade";
    ssi on;
    proxy_set_header X-Forwarded-Proto https;
    proxy_pass http://puma_example.it;
    # limit_req zone=one;
    access_log /home/deploy/apps/example.it/shared/log/nginx.access.log;
    error_log /home/deploy/apps/example.it/shared/log/nginx.error.log;
  }

  location ^~ /images/ {
    expires max;
    add_header Cache-Control public;
  }

  location ~ ^/(assets|packs)/ {
    gzip_static on;
    brotli_static on;
    expires max;
    add_header Cache-Control public;
  }

  location = /50x.html {
    root html;
  }

  location @503 {
    error_page 405 = /system/maintenance.html;
    if (-f $document_root/system/maintenance.html) {
      rewrite ^(.*)$ /system/maintenance.html break;
    }
    rewrite ^(.*)$ /503.html break;
  }

  if ($request_method !~ ^(GET|HEAD|PUT|PATCH|POST|DELETE|OPTIONS)$ ){
    return 405;
  }

  if (-f $document_root/system/maintenance.html) {
    return 503;
  }
}

You need to have separate server blocks for your www and non-www domains.

server {
    listen 443 ssl http2;
    listen [::]:443 ssl http2;
    ssl_certificate ...
    ssl_certificate_key ...
    server_name example.it;

    return 301 https://www.example.com$request_uri;
}

server {
    listen 443 ssl http2;
    listen [::]:443 ssl http2;
    ssl_certificate ...
    ssl_certificate_key ...
    server_name www.example.it;

    ... rest of configuration ...
}