NextCloud AIO Remote Data Help

I don't know if I'm stupid or if NextCloud's instructions are stupid, it's probably me and subsequently I'm struggling.

For all of my Docker stuff, I move the config directory to my opt folder with a simple

    volumes:
     - /opt/APPNAME/config:/config

And generally have the data on a remote drive like

    - music:/music

volumes: 
  music: 
    driver_opts:
      type: "nfs"
      o: "addr=192.168.X.XXX,nolock,soft,rw"
      device: ":/mnt/HD/Public/Shared Music"

This works perfectly for everything and I'm generally pleased with how things run. But NextCloud is throwing a bunch of words at me and I don't get it. Why can't it be as simple as what I'm already doing? Why do I have to declare

    environment
      - NEXTCLOUD_DATADIR=
      - NEXTCLOUD_MOUNT=

And why is it pointing me to? https://github.com/nextcloud/all-in-one?tab=readme-ov-file#how-to-store-the-filesinstallation-on-a-separate-drive

Which just points you to https://www.guguweb.com/2019/02/07/how-to-move-docker-data-directory-to-another-location-on-ubuntu/

I'm looking at this Docker Compose like...

NextCloudPi was so simple to set up. If not for being stuck on v25, I'd have been happy with it. 🥺