Old slater switch, two screws one on either side, Two black wires & white wire on right side, red wire on left side, need to replace asap cause half lights in house don't work, but all the outlets do, and it's a double switch.

Replace with same type switch, take notes and/or photo before dissembly .

Don't fully understand, as you say only a screw on each side, with wires only attached to these 2 screws.
With what you describe,a single pole switch would work.
Double switch?