Agree that replacing a backing plate is a big job requiring a press and the right specialty tool.
@bloc did a recent write up on his journey taking this all apart to address wheel bearing noise.
And I am still suspicious that you have something else out of spec, like a wheel bearing. If thise wear spots were rubbing metal on metal and making noise all the time, the rusty backing plate alone could make sense, but since you only hear it intermittently while turning (I think you said that), something is moving in a way it shouldn’t, making it intermittent.