First of all, my terminology may not be the most official or correct, forgive me in advance.
I have this double-gang box, which holds two switches (switch1 and switch2 in the picture).
Switch1: simple switch, lights the corridor lights. The corridor lights have yet another switch on the other side of the room.
Switch2: dimmer switch, lights the living room lights, it's the only switch that controls the living room lights. BK and YL in the diagram refer to the labels on the switch.
Both lights and switches are connected to the same circuit (When I shut the circuit off, both of them go dead)
I would like to replace switch2 with a smart switch, preferably without running any new cables, but I can't figure out how to rearrange the cables. I've searched high and low for days and can't seem to find a single wiring diagram that matches what I have here.
I have a multimeter available if any testing needs to be done, but again, I don't know exactly what I should be looking for.
EDIT: Not shown in the diagram are 4 bare copper wires coming in the box from out of each of the cables, and attached to screws on the box.
Any help would be appreciated :)
Thank you so much!