000646,
That Rambam does NOT ever give a husband permission to strike his wife. The rest of the halacha that you omitted makes it clear that such issues are brought before a Beis Din, and witnesses are needed.
And yes, the Raavad disagrees and states that a woman is not compelled with lashes. And nowhere does it say that the husband can starve his wife. Look at Ishus 14:8: “she is not like a captive…”
Again, I think you have some pretty big misconceptions about the Torah.