3. Atheists cannot prove god doesn’t exist
This myth is almost true. Yes, atheists cannot prove God exists any more than a theist can prove he does. However, if the religious person is making the claim that God does exist and the atheist is rejecting the claim, the onus of proof is on the theist.
If some told you right now they could fly, it is not up to you to prove they cannot. You would ask them to prove it, and if they refused, you would call them a liar.
The argument that atheists cannot prove God doesn’t exist works in the exact same way. This is why you will actually find that the majority of atheists are “agnostic atheists” meaning they know you cannot know for certain god(s) do not exist, but they have concluded based on the evidence that there is unlikely one does, so they live life as if no god(s) exist.
Philosophically speaking, a theist is an agnostic theist as well, since neither side can prove beyond a doubt their position, they make up their minds based on how the perceive the evidence.
Someone on either side claiming to know certainty is a “gnostic” and is generally rejected by both sides as being somewhat dishonest in their ability to make such claims.