Linux + Nginx: NodeJS + WordPress + Symfony

Question

I have an Ubuntu server with Nginx running node and PHP both.

Requirements:

• www.example.com/ -> React App (Running with PM2)
• www.example.com/blog -> Running a WordPress Blog
• www.example.com/backend -> Running a Symfony app which is the API

Achieved:

• React App with PM2
• WordPress blog running at /blog with index.php rewrite.

Problem:

Symfony app that is supposed to run on /backend is instead running on /backend/web/app_dev.php and additionally app.php (production mode) throwing a 500 server error. (SCREENSHOTS ATTACHED)

The Nginx configuration is as follows:

# Default Server Settings
server {
        listen 80 default_server;
        listen [::]:80 default_server;

        root /var/www/html;
        index index.php app.php;

        server_name 100.100.100.100;

        location / {
                proxy_set_header X-Real-IP $remote_addr;
                proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
                proxy_set_header X-NginX-Proxy true;
                proxy_pass http://localhost:3030/;
                proxy_ssl_session_reuse off;
                proxy_set_header Host $http_host;
                proxy_cache_bypass $http_upgrade;
                proxy_redirect off;
        }

        # WORDPRESS SETTINGS
        location @blog {
                rewrite ^/blog(.*) /blog/index.php?q=$1;
        }

        location /blog {
                index index.php
                alias /var/www/html/blog;
                try_files $uri $uri/ @blog;

                location ~ \.php$ {
                        include snippets/fastcgi-php.conf;
                        fastcgi_pass unix:/run/php/php7.2-fpm.sock;
                }

                access_log /var/log/nginx/blog-access.log;
                error_log /var/log/nginx/blog-error.log;
        }

        # SYMFONY SETTINGS
        location @backend {
                rewrite ^/backend(.*)$ /web/app.php/$1 last;
        }

        location /backend {
                index app.php
                alias /var/www/html/backend/web;
                try_files $uri $uri/ @backend;

                location ~ \.php$ {
                         include snippets/fastcgi-php.conf;
                         fastcgi_pass unix:/run/php/php7.2-fpm.sock;
                }

                access_log /var/log/nginx/symposh-access.log;
                error_log /var/log/nginx/symposh-error.log;
        }

        location ~ /\.ht {
                deny all;
        }
}

UPDATED SYMFONY SETTINGS (Still not working):

# SYMFONY SETTINGS
location /backend {
        index app.php;
        alias /var/www/html/backend/web;
        try_files $uri $uri/ /backend/web/app.php?$args;

        location ~ \.php$ {
                    include snippets/fastcgi-php.conf;
                    fastcgi_pass unix:/run/php/php7.2-fpm.sock;
        }

        access_log /var/log/nginx/symposh-access.log;
        error_log /var/log/nginx/symposh-error.log;
}

RESULT: