You can leave it.

As long as you ran systemctl daemon-reload, you should be able to try sleeping without needing to reboot.

It might be due to https://github.com/systemd/systemd/issues/33083.

Try disabling user session freezing when sleeping:

sudo systemctl edit systemd-suspend.service

Add the following to the file:

[Service]
Environment="SYSTEMD_SLEEP_FREEZE_USER_SESSIONS=false"

Reload systemd:

sudo systemctl daemon-reload

After that, try sleeping and waking again.

What filesystem are you using on the external drive? If it is NTFS or FAT, they won’t store permissions on the filesystem, which would explain why the owner/group changes are not persistent. To fix that, you can set the uid/gid on mount in your fstab.

/dev/mapper/YOUR_DRIVE /path/to/mnt <fstype> rw,uid=<jellyfin_uid>,gid=<jellyfin_gid>,dmask=0002,fmask=0113

Are you using the default bridge? I have a similar setup (with Traefik instead of NPM), and for each compose file am using separate networks for the internet, proxy, and backend services.

services:
  some_service:
    ...
    networks:
      - frontend_network
      - proxy_network
      - backend_network
  backend_service:
    ...
    networks:
      - backend_network
networks:
  frontend_network:
    driver: "bridge"
  proxy_network:
    driver: "bridge"
    internal: true
  backend_network:
    driver: "bridge"
    internal: true