To verify, have you tried entering the share folder name in the input box on the second line that says "SMB Share or Path"? Have you also tried using username "guest" and password "1234" as well (apparently, that should be a default user account for unraid). Lastly, have you tried creating a smb user in unraid?
I'm using multiple libraries to get smb to work. If the share name is present, the player will use libsmb2. If the share name is missing, the player will fallback to using smbj-rpc, which attempts to use the rpc protocol to enumerate the shares, but it's an experimental/incomplete library, so it might not be able to enumerate your shares. That's why I recommend inputting the share name into the box.
I'm not aware of any open source libraries that support NFS. I might be able to add SMB1 support, but I think SMB2/3 is faster, so it'd be best if we can figure out how to get smb2 to work with your unraid server. Else, does unraid support DLNA? Or would it be possible to set up XBVR so you can run an http server to host your videos?