Sorry but Huxley’s invention of the word agnostic categorically demonstrates that its etymology is less related to its Greek roots (without & knowledge) than it relates to the Gnostic religion associated with the early church.
Seems the Gnostics were famously unbearable know-it-alls willing to make up absurd claims to promote their arguments. With that in mind, in 1869 Thomas Huxley tired of witnessing theist and atheists argue back and forth like know-it-all Gnostics, he calls himself an A_Gnostic, and the word caught on.
You can source that story to “Agnosticism 1889” By Thomas Huxley. Atheists obviously don’t like to admit that he was so appalled by their know-it-all-ism that he invented and used his agnostic principle to dismiss both theism and atheism, and both have been trying to redefine and misuse the word for almost 150 years. Nevertheless the word is obviously his to define, no matter what the atheists say.