This might be a stupid question.
I understand the reason there’s a second data line on the WS2815 LED Strip but where does the second data line connect on a NodeMCU?
Does it common connect to the data pin or does it connect to a second pin with programming needed when the primary fails?
Does WLED need to be set up different for the second data line?
It does not.
Check manufacturers specifications to be sure, but normally it is grounded.