First of all, congratulations! These kinds of questions are extremely challenging to even ask from within certain philosophical frameworks, and the fact that you're here at all means that you've accomplished something exceptional. Further, by using the question of miracles specifically, you've focused on empirical, testable claims with verifiable consequences. The epistemology that you're associating with atheism or agnosticism is fundamentally the ability to ask exactly these questions, the habit of doing so reflexively, and the willingness to follow those questions to real answers.

The basic Bayesian response to the question of miracles isn't just "are they lying, or is there a God?" Ask the question a different way: in a hypothetical universe in which Christianity is false, how many claims of miraculous events do we expect? In a hypothetical universe in which Christianity is true, how many true (and false!) claims of miraculous intervention do we expect? Do we expect a difference in the kind of miracles that are claimed to occur? For example, we experience people claiming that God cured infertility or cancer, but never people claiming that God cured their amputation. It's an interesting discrepancy, and which universe is that most consistent with? Etc. Don't think about it in terms of picking apart each individual claim. Just ask yourself about an interventionist God in terms of your honest expectations for such a God, and consider the world-as-it-is in comparison. Use the miraculous as a prediction that can succeed or fail, rather than simply as an explanation that is immune to correction.