I have a feeling you’ll need to install the NFS server package on the Vero “server” box.
sudo apt-get update
sudo apt-get install nfs-kernel-server
You’ll also need to configure an exports file for NFS, if you choose this route. Have a look at this post for further details Configuring fstab based NFS share mounts - #10 by grahamh
As for your iperf3 figures, they are disappointing: relatively slow and highly variable.
Are you still using WiFi?