It sounds like you bought your machine from the same place I did.
Mine is flawless... I suppose the variation in build quality is expected at that price really. I probably dropped lucky.

I'm sure you've tried this, but have you.. tried swapping around the axis driver PCB's to make sure one of them is faulty and that it's not
some sort of problem with the stepper itself?

I haven't tried pressing out the bearing in a vice.. but that's how I'd do it. bearings are tougher than you think. Just don't hammer anything!