If you want to use transmission as your torrent client I recommend checking out https://github.com/haugene/docker-transmission-openvpn . There are some additional configuration changes needed for mullvad but it should be straightforward.

Here’s my docker-compose.yml for nextcloud (with minor privacy changes) that includes onlyoffice and drawio containers. SSL is not included and should be handled by NPM and you’ll need a proxy host for both drawio and onlyoffice. I use NPM in docker so I just add it to the docs network instead of exposing any additional ports. For onlyoffice the secret key gets regenerated each time the container starts so you’ll need to update onlyoffice setting in nextcloud each time (unless someone has a better solution). You can get the secret key by logging into the onlyoffice container and running

cat /etc/onlyoffice/documentserver-example/local.json

I’ve been running this solution for a few years without any major issues.

docker-compose.yml

version: '3.5'

networks:
 docs:
  name: docs 
  driver: bridge

services:
 nextcloud:
  image: linuxserver/nextcloud
  container_name: nextcloud
  environment:
   - PUID=1000
   - PGID=1000
   - MYSQL_DATABASE=nextcloud
   - MYSQL_USER=nextcloud
   - MYSQL_PASSWORD=P@ssWord321!
   - MYSQL_HOST=nextcloud_db
   - TZ="America/Chicago"
  volumes:
   - /home/user/docker/configs/nextcloud:/config
   - /home/user/docker/configs/nextcloud_data:/data
  restart: unless-stopped
  depends_on:
   - nextcloud_db
  networks:
   - docs 

 nextcloud_db:
  image: linuxserver/mariadb:110.4.21mariabionic-ls31
  container_name: nextcloud_db
  restart: always
  environment:
   - PUID=1000
   - PGID=1000
   - MYSQL_ROOT_PASSWORD=P@ssWord123!
   - MYSQL_DATABASE=nextcloud
   - MYSQL_USER=nextcloud
   - MYSQL_PASSWORD=P@ssWord321!
  volumes:
   - /home/user/docker/configs/nextcloud_db/mysql:/config
  restart: unless-stopped
  networks:
   - docs 

 onlyoffice:
  image: onlyoffice/documentserver
  container_name: onlyoffice
  restart: always
  depends_on:
   - nextcloud
  networks:
   - docs 

 image-export:
  image: jgraph/export-server
  container_name: nextcloud-drawio-export
  networks:
   - docs 
  volumes:
   - ./fonts:/usr/share/fonts/drawio
  restart: unless-stopped

 drawio:
  image: jgraph/drawio
  container_name: nextcloud-drawio
  networks:
   - docs 
  depends_on:
   - image-export
  environment:
   - VIRTUAL_HOST=drawio.example.com
   - VIRTUAL_PORT=8080
   - EXPORT_URL=http://image-export:8000/
  restart: unless-stopped