The definition I remember growing up with of agnostic is somebody who thinks there is not enough evidence to tell if there is a God or not. But in regard to Theism (being belief in God) and Atheism (belief there is no God) is kind of a neutral position.
I also think it a natural extension for the person that lacks belief about God one way or the other and also is not sure whether there is enough evidence to decide the matter under the heading agnostic, until I learn a word specific to them.
For the person that thinks there is a God but is not sure the God is the one common in religion, I think the most specific term is Deist, which I understand to be a specific kind of Theist--although I did watch a new atheist you-tuber try to claim that such a person should be counted as an Atheist...
I have heard a specialized term for people that maintain that the question of God lacks proper definition so is unfathomable and does not have an answer. So in my vocabulary it seems I would have to put them in the agnostic camp until I look up and remember that term ;-).
In any case my point was, I don't think it proper to expand the term Atheists to include the various people I would call Agnostic, and even more so not expand it to include Deists.