Node-RED Victron extension is not working. (node-red-contrib-victron)

For those who, like me, are deploying a fresh Node Red on Venus OS v3.6x and discover that none of the Victron nodes are working: the cause and fix are explained here.

In short, one should deploy a Victron Node first (ignore the warning at deploy time), then the nodes will start working and can be configured & properly deployed.