Nginx + CI4 + MariaDB + phpMyAdmin config

Hello there!

Can someone give me some advice how to set up Nginx correctly in the following situation? 
I've a domain and SSL, CI4 is up and running correctly. I succesfully set-up MariaDB, the service is up and running on Debian 10 (buster). Multiple guides across the internet says, I need to add something like that to the nginx config:

server {
  listen 80;
  server_name [b]domainname[/b];
  root [b]/usr/share/phpMyAdmin[/b];

  location / {
      index index.php;
  }

## Images and static content is treated different
  location ~* ^.+.(jpg|jpeg|gif|css|png|js|ico|xml)$ {
      access_log off;
      expires 30d;
  }

  location ~ /\.ht {
      deny all;
  }

  location ~ /(libraries|setup/frames|setup/libs) {
      deny all;
      return 404;
  }

  location ~ \.php$ {
      include /etc/nginx/fastcgi_params;
      fastcgi_pass 127.0.0.1:9000;
      fastcgi_index index.php;
      fastcgi_param SCRIPT_FILENAME [b]/usr/share/phpMyAdmin[/b]$fastcgi_script_name;
  }
}

However, I don't really know where to add those in my config, which is the following:

# Redirect all traffic to HTTPS
server {
  listen 80;
  return 301 https://$host$request_uri;
}

server {

  listen 443 ssl default_server;
  server_name domain.com;
  ssl on;
  ssl_certificate /ssl/domain.crt;
  ssl_certificate_key /ssl/domain.com.key;

  ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
  ssl_ciphers HIGH:!aNULL:!eNULL:!EXPORT:!CAMELLIA:!DES:!MD5:!PSK:!RC4;
  ssl_prefer_server_ciphers on;

  root /var/www/codeigniter/public;
  index index.php index.html index.htm;

  charset utf-8;

  location / {

      try_files $uri $uri/ /index.php$is_args$args;

  }

  location ~ \.php$ {
  #CORS Headers
      if ($request_method = 'OPTIONS') {
          add_header 'Access-Control-Allow-Origin' '*';
          add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
          #
          # Custom headers and headers various browsers *should* be OK with but aren't
          #
          add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range';
          #
          # Tell client that this pre-flight info is valid for 20 days
          #
          add_header 'Access-Control-Max-Age' 1728000;
          add_header 'Content-Type' 'text/plain; charset=utf-8';
          add_header 'Content-Length' 0;
          return 204;
      }

      if ($request_method = 'POST') {
          add_header 'Access-Control-Allow-Origin' '*' always;
          add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS' always;
          add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range' always;
          add_header 'Access-Control-Expose-Headers' 'Content-Length,Content-Range' always;
      }

      if ($request_method = 'GET') {
          add_header 'Access-Control-Allow-Origin' '*' always;
          add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS' always;
          add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range' always;
          add_header 'Access-Control-Expose-Headers' 'Content-Length,Content-Range' always;
      }

      #Process the request with FPM
      include snippets/fastcgi-php.conf;
      fastcgi_pass unix:/run/php/php8.0-fpm.sock;

  }

  error_page 404 /index.php;

  # deny access to hidden files such as .htaccess
  location ~ /\. {
      deny all;
  }
}

Thanks in advance.