And it wouldn't kill just Akatosh, but all gods are dead in the Dawn. All we have is Anu.
I suppose it might be helpful to subdivide the Dawn for clarity. It is during the dawn that the other gods came about and during the dawn (or early merethic? I don't really see much of a distinction between the two) that they made Tamriel and became mortal. So yes, for a part of the Dawn there was only Anu/Padhome, but there were also times when a multitude of gods existed. The way I understand it, the Altmer (in general, Psijics being one exception) want to return to the time just before Mundus when there were tons of gods and no mortal limitation. The Dwemer (and, I would think, some Alessians) were looking to get back to the singular Anu state, or even the Godhead before it. Hence the Endeavor and Numidium (singular ascension, "individual beyond all AE" and all that), versus the Elven Towers (returning existence to what it was before the convention).
Obviously not fact-checked, which will probably come back to bite me in the butt
I really need to stop posting one liners