I’ve had trouble getting it apart too, nice to have someone to share the misery with.
Try heat and oil, if the oil is squirted after heating it’ll be drawn further in. I was able to
get a stuck brake rotor off this way which is similar in that the metal had corroded together.
This isn’t my biggest problem so I’ve put it on the back burner. I’ll give it another try soon and
get back to you.