Anal Intercourse
First of all- the arabic word أذى as far as I am aware does not mean impurity; it means pain. The issue is the relation between the verses. I agree that the primary one implies that vaginal intercourse is the one that is allowed because that’s the ‘natural’ way. However if this is taken to be a restriction then the second ayah saying ‘approach them however you want’ becomes meaningless. Islahi sahab has written a paragraph but barely said anything about this. If there is only one passageway to approach your wife then how can one approach them however they want?
If I say ‘here is a pen use it on this specific paper’, then I say in the next sentence ‘use the pen on whatever paper you want’ then there is a contradiction.