Sure, normally I start off with arguments for metaphysics, usually the big-bang theory. A clear majority are purely materialists, it's pretty easy to start the argument with causality.
How are we here? If it is through big-bang, then it is creation ex nihilo, as there was a nothing, then there was a something. Ergo, something cannot come from nothing, there was a creation. Since there was a creation, this implies a reality to existence that pure materialism cannot explain, and this is corroborated by the understanding of the Scriptures. This also ties into the rationality of monotheism.
Since they are atheist/materialist, they are required to deny a creation from nothing, so it either ends 1. denying the big bang as a theory 2. eternal regress 3. parallel universes and blah blah
If it's 1., they are refuting science as any creationist does to evolution, this is enough to make any reddit tier atheist stop and think for a second.
If it's 2., they are condemning themselves to a fringe understanding that they usually cannot substantiate at all.
If it's 3., they want it both ways, to deny a creation but still keep metaphysics, which wouldn't even really deny God, because how can God be contained by contingency?
If they're an absolute skeptic, you must point out that they're not having a real standpoint on existence, they're just throwing up their hands into the air and just wanting to have their cake and eat it too.
materialism is incredibly easy to debunk