I am trying to replace 2 current 3 way switches with 2 new
GE/Jasco Z-Wave In-Wall Smart Dimmer with an add on switch.

Unfortunately the wiring setup looks nothing like
anything that I can even find online. 2
wires going back up to the light fixture, but I'm not sure where they are going.

Some things I found "interesting"

Note: "C1B" = Cable 1 Black Wire; These scenarios are under the
premise that the switches have been removed and the wires are just
"hanging" there and the breaker is turned ON.

1. If C1B and C2B connected and C1W /C2W connected the lights turn on. Nothing in C3 or C4 is hot when I do this.

2. Connecting
C1B to C3B all of C4 (C4W, C4R, C4B) turn hot

I have to admit that I have no idea how this is wired or how
to wire in these new switches. Any
recommendations would be GREATLY appreciated!