So I got some smart switches (Kasa HS210), and being relatively handy thought I could wire them up alright, but I guess I'm in a bit over my head due to having a "dead end 3-way"? Using the original switches I was able to control lights at both ends, but with the smart switches, not so much. They either fail to work, or result in the lights rapidly switching on and off, depending on how the wiring is.
Incoming line junction box has 4x cable runs, but only one has a red traveler wire, which matches up with the downstream dead-end. Not 100% sure where the others go, but I'm assuming to the lights themselves and my back patio since that turns off when I switch the breaker off.
I think I have the line side wired up correctly, but I'm at a loss as to what to do at the dead-end side of things. I've seen mention of using the neutral as a common wire on the dead-end side, but I'm fairly sure my switches require a neutral.
Appreciate any insight