This isn't an RET forum, go there to ask RET-related questions.
You can't ignore a theory that goes against your theory.
How does a core form in RET?
Pressure, heat, and lack of cooling. When the Earth formed, according to a theory that is
not RET (but assumes RET is correct), it was just a sphere of magma. The crust cooled, and everything else hasn't, and probably won't.