Looks like a cpu/gpu type power connector. Even if its a standard plug does not mean its a standard pin out ! Craft computing on YouTube had what looked like a standard plug in his server but it had a 12volt and ground switched, so would have caused some real damage
I run snapraid and mergerfs, as the nas storage. Not much changes on my NAS and the stuff I really care about like my pictures and videos are on a small ZFS pool. Both are directly on proxmox, meaning I can just plug them in to another Linux machine and research if it all goes sideways. Its all shared from the host via SMB NFS or for jellyfin and immicher its a moint point for the container