Instead of the dedicated WidgetLED commands, I use this generic vPin type of processing for my multi-virtual LED projects
Blynk.virtualWrite(i, 255); // Set LED to full intensity
For example, to turn all 72 of them “simulated off”, AKA all black… True off would be setting them to 0 for the value.
for (int i = 0; i <= 71; i++) {
Blynk.setProperty(i, "label", " "); // Set LED Label to blank
Blynk.setProperty(i, "color", "#000000"); // Set LED colour to black
Blynk.virtualWrite(i, 255); // Set LED to full intensity
}