Finding arguments unconvincing would still be definitionally agnostic. To be a gnostic atheist, you have to posit an argument that no deity/whatever could exist, not just that’s it’s exceedingly unlikely.

The vast majority of atheists are agnostic atheists, and “we don’t know” is that in a nutshell. Gnostic atheists who “know” there is no god are rather rare but very loud.