So E2 dehydration reaction of primary alcohols form an elimination product and a SN2 product which was an ether.

My book gives me the mechanism reaction for the E2 elimination that's happening.

But before that I had read on the same book a few sections before that the SN2 reaction for a primary alcohol formed a substitution product, which was an alkyl halide!

So now I am very confused as to what happens with a primary alcohol in an SN2 dehydration reaction

Can someone explain? In both reactions dehydration occurs so I really don't know

Does a SN2 dehydration reaction form an ether as well as an alkyl halide?

It can do both. Which one is favoured can be changed by tuning the conditions (strength of the base, solvent, temperature, etc.) or is selected for based on inherent features of the molecule.

 

With that said, I would argue that the conversion that they have outlined is best done with other halogenating units.

I don't think that S_N2 dehydration is clear terminology. E2 dehydration makes more sense if we are discussing an elimination.