So what you have in your flow is a Dashboard Switch, passing it’s value to a Blynk Bridge node.
I’ve never used the Blynk Bridge node, and don’t really see what value it has within Node-Red, because in my view Node-Red eliminates the need for using Bridge.
I don’t have the Node-Red dashboard installed in my Node-Red setup, once again, I don’t really see the point of it. As a result, I can’t demonstrate what a flow would look like because I don’t want to install the dashboard.
Instead, I’ll represent it like this:
Dashboard Switch Node ----> Blynk Write Node connected to V1
Blynk Write Event Node connected to V1 ----> Dashboard Switch Node
With this arrangement, switching the dashboard switch will update the Blynk widget on V1 and when V1 changes it will update the dashboard switch.
The only thing to look out for is that the dashboard switch and the Blynk widget both use the same values (0=off, 1=on for example).
If you want to learn more about Node-Red and Blynk then take a look at this thread:
Pete.