Thanks for the pictures but you need very detailed pictures so you know exactly which wires are going to what on your switches. I am trying to trace the wires exactly from each box going to what on the switches and I still can’t tell. Take a look at the pictures at this posting for examples of the details needed to help you quickly
Forget the red for now.
You need to determine where the romex bundle with the hot coming in from breaker. Trip the breaker. Then disconnect your wires from the 3-way switches (remember you have great pictures to put everything back incase you need to). Flip the breaker back on, the power will only be showing up on one of the romex blacks. That romex black label as your LINE and the white is NEUTRAL for the primary GE switch.