You are not answering the question I asked. To repeat, with the part you are glossing over in bold:
And for those whose atheism is reinforced with each new scientific discovery, is that confirmation bias free?
Now a possible answer is “nobody’s atheism is ever reinforced by a new scientific discovery.” That would be consistent with your statement:
but it would be inconsistent with the legions I’ve heard and read over the years who do in fact claim that scientific advances only serve to strengthen their lack of belief.
So if you believe there are such atheists, who make such a claim, are they free of confirmation bias?
Or are you claiming no such atheists exist?