Uppercase to lowercase in nginx module

I have a nginx module which is redirecting the user to different folders depending on the URL. The logic is this: mysite.site/folder1, mysite.site/folder2, mysite.site/folder3 etc. What I want to do is to enforce that if the user writes mysite.site/Folder1 my server converts this to mysite.site/folder1 because otherwise the user is receiving 500 Internal Server Error. Any suggestion? this is my module:

server {

    listen 443 ssl;

    set $root_path '/var/www/mysite.site';
    root $root_path;

    index index.html index.htm index.nginx-debian.html index.php;

    server_name mysite.site www.mysite.site;

    location /folder1{

      alias /var/www/mysite.site/folder1;
      location ~ \.php$ {
           fastcgi_pass unix:/run/php/php7.4-fpm.sock;
          include fastcgi_params;
          fastcgi_param SCRIPT_FILENAME $request_filename;
      }
    }
    location /folder2{

      alias /var/www/mysite.site/folder2;
      location ~ \.php$ {
           fastcgi_pass unix:/run/php/php7.4-fpm.sock;
          include fastcgi_params;
          fastcgi_param SCRIPT_FILENAME $request_filename;
      }
    }
    location /folder3{

      alias /var/www/mysite.site/folder3;
      location ~ \.php$ {
           fastcgi_pass unix:/run/php/php7.4-fpm.sock;
          include fastcgi_params;
          fastcgi_param SCRIPT_FILENAME $request_filename;
      }
    }

    ssl_certificate /etc/letsencrypt/live/mysite.site/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/mysite.site/privkey.pem; # managed by Certbot

}

server {
    if ($host = www.mysite.site) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


    if ($host = mysite.site) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


    listen 80;

    server_name mysite.site www.mysite.site;
    return 404; # managed by Certbot

}