I want to run nextcloud on a path behind an nginx reverse proxy. The nginx reverse proxy is already configured and works fine for other services. This is my nextcloud specific location:

        location /nextcloud-demo {
                client_max_body_size 10G;
                proxy_request_buffering off;

                # HTTP 1.1 support
                proxy_http_version 1.1;
                proxy_buffering off;
                proxy_set_header Host $http_host;
                proxy_set_header Upgrade $http_upgrade;
                proxy_set_header Connection $http_upgrade;
                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 $http_x_forwarded_proto;
                proxy_set_header X-Forwarded-Ssl $scheme;
                proxy_set_header X-Forwarded-Port $http_x_forwarded_port;

                # Mitigate httpoxy attack (see README for details)
                proxy_set_header Proxy "";

                proxy_pass http://127.0.0.1:8082;
        }

And this is how i start the nextcloud container:

pi@piserver01:~/nextcloud-demo $ docker run -d --restart always --name nextcloud-demo -p 8082:80 -e NEXTCLOUD_TRUSTED_DOMAINS=example.com -e OVERWRITEWEBROOT=/nextcloud-demo -e NEXTCLOUD_ADMIN_USER=nextcloud-demo-admin -e NEXTCLOUD_ADMIN_PASSWORD=xxx -e SQLITE_DATABASE=db nextcloud:19-apache
3d753b5252b8bc51a29608bd9a63cd10374a94d9aa61bcbca5f588fe3671689b
pi@piserver01:~/nextcloud-demo $ docker logs -f nextcloud-demo
Initializing nextcloud 19.0.2.2 ...
Initializing finished
New nextcloud instance
Installing with SQLite database
starting nextcloud installation
Nextcloud was successfully installed
setting trusted domains…
System config value trusted_domains => 1 set to string example.com
AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 172.17.0.4. Set the 'ServerName' directive globally to suppress this message
AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 172.17.0.4. Set the 'ServerName' directive globally to suppress this message
[Sat Aug 29 19:41:50.649446 2020] [mpm_prefork:notice] [pid 1] AH00163: Apache/2.4.38 (Debian) PHP/7.4.9 configured -- resuming normal operations
[Sat Aug 29 19:41:50.649655 2020] [core:notice] [pid 1] AH00094: Command line: 'apache2 -D FOREGROUND'
172.17.0.1 - - [29/Aug/2020:19:42:39 +0000] "GET /nextcloud-demo HTTP/1.1" 302 417 "-" "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:80.0) Gecko/20100101 Firefox/80.0"
172.17.0.1 - - [29/Aug/2020:19:42:39 +0000] "GET /nextcloud-demo/ HTTP/1.1" 302 1014 "-" "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:80.0) Gecko/20100101 Firefox/80.0"
172.17.0.1 - - [29/Aug/2020:19:42:41 +0000] "GET /nextcloud-demo/login HTTP/1.1" 302 909 "-" "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:80.0) Gecko/20100101 Firefox/80.0"
172.17.0.1 - - [29/Aug/2020:19:42:41 +0000] "GET /nextcloud-demo/login HTTP/1.1" 302 909 "-" "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:80.0) Gecko/20100101 Firefox/80.0"
172.17.0.1 - - [29/Aug/2020:19:42:41 +0000] "GET /nextcloud-demo/login HTTP/1.1" 302 909 "-" "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:80.0) Gecko/20100101 Firefox/80.0"
172.17.0.1 - - [29/Aug/2020:19:42:41 +0000] "GET /nextcloud-demo/login HTTP/1.1" 302 909 "-" "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:80.0) Gecko/20100101 Firefox/80.0"
...

This setup results in a redirect loop (HTTP 301 and 302) when opening https://example.com/nextcloud-demo.

Do you see any problems with my configuration? I'm not entirely sure how the other OVERWRITE* env vars come into play here.