What makes it unreliable?

I run a Debian server on proxmox with a nfs share to an openmediavault VM, just like you intend to. Works like a charm. When you search for Media Server on smarthomebeginner.com you can find a setup with Docker. I really recommend it, Docker makes it so much easier.

I'm gonna look into that! Borgmatic looks a lot easier than borg, but that CLI still scares me. I like working with Linux commands but something new like backups makes me want to click in a GUI to set everything up.

It looks good, but I think it's difficult to work without a central view to view all the machines statuses. How can you make sure all your machines have run a good backup?

I'm going to try that for my servers! What do you use for your files (music, photos and such)?

I added this! Your solution + chmod 0770 on my folder made it work. Thanks for helping!

how can i check which accounts are used? I think my normal user account sets up docker, with uid & gid = 1000. I don't think i created an account in the container so probably root.

When I run: docker exec -it nextcloud bash I get: root@nextcloud:/var/www/html#, does this mean it uses www?

I want to try that, but i've got to add: i want to access this folder from my desktop too. i added it the same way in /etc/fstab and it worked instantly

I guess I just want to make sure the pictures are safe. Next to that I'll backup my /home/user folder, but next to that it's not that hard to rebuild my VMs.