Hmm I’m sorry to hear that I have build the above setup (without proxmox) in a hyper-v vm on my own PC and I did get it working with SMB and it seems to be running pretty well
Maybe I’ll mount the share directly to the container and connect it through there aswell. I’m not too sure yet
I built it in a VM on my home PC to try it all out now
I made a truenas user ‘nextcloud’ with a password
Shared a folder over SMB and gave the user permission to it
Used the ‘external storage’ plugin in NextCloud to add the SMB share with the ‘nextcloud’ user and then gave the ‘family’ nextcloud group access to this folder
Where exactly are you getting stuck? Maybe I could give a more detailed explanation