Ryuk Ransonware Encrypt Image files

I've an old Proxmox 4.4 running some VMs, a Ryuk virus attacks my network, and it has rename the image files as .ryk, and these VMs are corrupted.

I've backups for these VMs on an NFS share, but new Proxmox 6.4 can not connect to these NFS share, so I can't restore any VM from there.

So how can I recover these VMs?

thanks for your help
Alfredo