Wordpress on Synology NAS with Nginx reverse proxy - Redirect Loop

Hello, I am troubleshooting this for a long time now, but I can’t find a solution by myself - hope you can help me. I installed the Wordpress package on my Synology NAS, which serves Wordpress on http://192.168.0.101/wordpress

Now I want to access the site from the internet - therefore I set up a reverse proxy with Nginx - I use this proxy for some internal sites, everything works except Wordpress, where it ends either in an redirect loop, or a “page not found” Wordpress site.

Wordpress is hosted on the Synology Nas with no SSL, because I want that the SSL encryption is served by the reverse proxy, so that I don’t need to install the certificate on the Synology Nas.

I already tried to disable Wordpress redirecting with remove_filter(‘template_redirect’,‘redirect_canonical’); in the theme functions.php, but no success.

Thank you in advance for your much appreciated help!

My Wordpress website address is set to: https://blog.mydomain.com/wordpress

My Nginx config for this subdomain part:

server {
	listen 443 ssl http2;
	listen [::]:443 ssl http2;
	index index.php;
	server_name blog.mydomain.com;

	# reverse proxy
	location / {
		proxy_pass http://192.168.0.101/wordpress/;
		include nginxconfig.io/proxy.conf;
	}

	# SSL
	ssl_certificate /etc/letsencrypt/live/mydomain.com/fullchain.pem;
	ssl_certificate_key /etc/letsencrypt/live/mydomain.com/privkey.pem;
	ssl_trusted_certificate /etc/letsencrypt/live/mydomain.com/chain.pem;

	proxy_ssl_session_reuse on;
	proxy_ssl_verify       on;
}

#Forward HTTP to HTTPS

server {
   listen 80;
   listen [::]:80;
   server_name blog.mydomain.com;
   return 301 https://$server_name$request_uri;

}

NGINXCONFIG.IO proxy.conf

proxy_http_version	1.1;
proxy_cache_bypass	$http_upgrade;

proxy_set_header Upgrade			$http_upgrade;
proxy_set_header Connection 		"upgrade";
proxy_set_header Host				$host;
proxy_set_header X-Real-IP			$remote_addr;
proxy_set_header X-Forwarded-For	$proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto	$scheme;
proxy_set_header X-Forwarded-Host	$host;
proxy_set_header X-Forwarded-Port	$server_port;