I’m at work so I don’t have the time to study all the diagrams but, from a quick look, your wiring looks like what I just did last night. Hopefully, this is helpful and not just a wasted read.
I wired in one of the old model switches (DZS15) along with the associated remote but I’m pretty sure the wiring is the same. In my case, the line and load were located in the same box and the electrician used a 14-3 cable to run to the remote. In the 14-3, he used black to pass hot and the white and red as the two travelers. This left me with no useful neutral in the remote box.
After studying the diagram for a bit, I realized that one of the travelers is actually just passing a constant hot back from the remote in box two to the switch in box one. With that in mind, I ended up rewiring the 14-3 so that I had black as hot, white as neutral, and red as the single traveler. So, on the remote end, I put white into WH, black into BL, and red into YL/RD. On the switch side, I put white into WH, black into RD, red into YL/RD, and connected a new black wire from the hot wire nut bundle into BL. Without looking at the install instructions, it’s possible I’m switching where the 2 black wires went on the switch but, basically, I put a new hot wire where traveler 2 would have plugged in.
Hope that helps!