It really sounds like your brakes are screwed up. All around disc brakes aren’t THAT preferential to the front. Also, if your rear rotors aren’t really getting used and are just all rusty, why do you keep buying replacement rear rotors? Just take a wire wheel to them and slap them back on. Same with pads. Why are they being ruined every two years if they aren’t getting used?

All that aside, do you have small drum brakes for your ebrake in the rear, or is it only disc brakes? Many have a “drum in hat” setup where the e brake doesn’t use the disc brakes, but if you do have disk only, you could try moving a bit while you activate the e brake and see if it polishes off your rust and stuff. E brakes of either kind only lock back wheels.