Rather than using the API to fetch data (presumably you’re doing this on the ESP32) you’d probably be better using it to push data from each of your slave devices if the LED status changes.
This way, you aren’t polling each of the slave devices to see if their switch values have changed. Instead these devices will push the new value only when it changes.
Pushing data on a virtual pin in this way will automatically update an LED widget attached to that datastream, and will cause the `BLYNK_WRITE(vPin) callback for that pin to trigger, allowing you to switch physical LEDs at the same time.
There is some example code for you to use in the EP8266 link on this post…
As far as limits are concerned, I think the limit is 500,000 updates per 24 hour period…
Pete.