@selzero @nitpicking yes, you are misunderstanding.
«Does a deity exists?»
The agnostic answer is «it's impossible to know». This is not a yes, it's not a no, and it's not even a maybe.
Which is why agnostic strong atheism is a thing (it's impossible to know THEREFORE there are no gods), which, I'll remark, does NOT contemplate the possibility that they do exist, but is still agnostic (in fact, it relies on agnosticism as a rationale to deny the existence of the gods).