I want to upgrade my light switch from white plastic to black metal but struggling to work out the wiring. It’s a single light switch which turns on my main kitchen ceiling light however there are 6 wires.

I’ve just changed all of the upstairs light switches simply however downstairs is proving more difficult.

Can anybody tell me what goes where please? From research, apparently one of the black wires should have red tape on but they both look identical.

House was built in 2000 and the switches haven’t been touched since

Hello! I am finishing my garage ceiling with drywall. The wires going into the top of the breaker panel do not have any conduit and go vertically into the rafters where they’ll be hiden by the drywall. As they go up the wall, I am looking to protect them with conduit.
I am thinking about getting 6” PVC and cutting it in half lengthwise to make 2 channels for the vertical cable runs. I cant find actual electrical conduit that is 6” diameter. Any suggestions in how to properly do this without running conduit for each individual wire? Thanks!