NGINX + PHP, $_POST data comes empty after passing through nginx

Here is the issue, when i try to use NGINX (1.18) and PHP (7.4.3) with FPM (lastest from APT) i run into an issue where all of the POST data from my script returns as null

$_POST['name'];
// console after post: name is undefined

The URL i tried posting too:

/posts/new/post

(the user goes on /posts/new to make a new post, the $_POST request goes to /posts/new/posts)

here is my nginx config:

server {
        root /forum/;
        index index.php;
        server_name ***.net;
        location / {
                try_files $uri $uri/ =404;
        }
        location /posts/ {
                    try_files $uri $uri/ @rewrites;
        }
        # pass PHP scripts to FastCGI server
        #
        location ~ \.php$ {
                include snippets/fastcgi-php.conf;
                fastcgi_pass unix:/var/run/php/php7.4-fpm.sock;
        }
        location @rewrites {
         rewrite ^/posts/(?<id>[a-zA-Z0-9]+)$ /posts/?post=$id;
        }

    listen [::]:443 ssl ipv6only=on; # managed by Certbot
    listen 443 ssl; # managed by Certbot
    ssl_certificate /etc/letsencrypt/live/***.net/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/***.net/privkey.pem; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot

}

when i was building these scripts, they worked fine on the PHP built in testing server.

Also note: this server is behind a proxy, but this was tested behind the proxy (going to 192.168.x.x)

edit: also i forgot to state that the $_POST is via a XMLHTTP post via $.ajax from Jquery.

edit 2: Apon looking at the Headers Sent via the Script (on FPM) no post data is sent, but when using the testing server, the post data is sent

after about 2 hours of useless looking, a simple fix: change

        location / {
                try_files $uri $uri/ =404;
        }

to

        location / {
                try_files $uri $uri/ /index.php?q=$uri&$args;
        }

what caused this issue:

when running a query against an INDEX / (without /index.php) the query was not passed onto the /index.php, so all $_POST returned as NULL