Reliabilist and skeptical claims notwithstanding...(as pointed out by Conifold)
this is the crux of the atheistic Argument from Divine Hiddenness:
(1) Necessarily, if God exists, then God perfectly loves such finite persons as there may be.
(2) Necessarily, if God perfectly loves such finite persons as there may be, then, for any capable finite person S and time t, God is at t open to being in a positively meaningful and reciprocal conscious relationship with S at t.
(3) Necessarily, if for any capable finite person S and time t, God is at t open to being in a positively meaningful and reciprocal conscious relationship with S at t, then, for any capable finite person S and time t, it is not the case that S is at t nonresistantly in a state of nonbelief in relation to the proposition that God exists.
(4) There is at least one capable finite person S and time t such that S is or was at t nonresistantly in a state of nonbelief in relation to the proposition that God exists.
(5) So, it is not the case that God exists. (from 1 through 4)
(Source: Howard-Snyder, Daniel and Adam Green, "Hiddenness of God", The Stanford Encyclopedia of Philosophy (Fall 2022 Edition), Edward N. Zalta & Uri Nodelman (eds.), URL = https://plato.stanford.edu/archives/fall2022/entries/divine-hiddenness/.)
Having just gotten out of Catholic Mass, I know at least some Christians believe that God has a deep, unconditional, superhuman love for them, despite their failings. Also, I am a person who despite my non-belief would be thrilled to know that there is a grander arc to my existence than merely dying and being put in the ground. I would be more than open to some kind of evidence that (with high probability) is not (a) a hallucination/mental condition, (b) not naturally derivable (c) corroborated by others.
Taken together, I would be very hard-pressed to continue in my atheism at that point. Given I don't have any natural dislike of theism or the idea of the afterlife/god/higher power (actually the opposite), I would switch my views given the overwhelmingly large odds against this just being some mass hallucination or alien species playing a trick on us, which is something I would rate as less plausible than a God as an explanation of (a) - (c).
More in the vein of Schellenberg's argument above, I hope that I am sufficiently nonresistant to allow for more personal, direct conversion by God. I have said the "skeptic's prayer" sincerely at many points in my life but have yet to cross over to true belief (vs just motivated hope).
Example of Sufficient Criteria for Belief for this non-resistant non-believer:
(A bit tongue in cheek for fun)
Simultaneously, across all continents, a bright blue orb appears in the sky and all televisions start showing a dark screen with a blue circle in it, completely silent. Then a voice speaks, with each recipient hearing it in their native language, either directly from the orb or from the television.
I am what you refer to as God. I created this universe and constitute it. I have been watching you all develop over the eons, searching for, fighting about, arguing for, answers about me. Your technology and scientific sophistication have grown to the point that I am ready to set the record straight, with the hope that enough of this event will be reliably documented to ensure future generations are not confused.
I see you value science, and it has been mostly good to you, but not without much pain and violence as well. Therefore, I will offer you something that I hope speaks to my benevolence and my desire to rid you of your persistent worries of mortality and meaning. It will only be comprehensible to a small fraction of you, and even then you will need to work hard as it contains much that has yet to be discovered.
I offer you this: As you have discovered, your views of the very large and very small are not compatible. You have devised many ingenious attempts at this solution but lack the means to test your theories. I will give you the answer and the means to experimentally verify it. [God then goes on to describe a variant of a theory in quantum gravity, displaying the symbols on its surface as it speaks. It then says that before it departs, it will keep a symbol in the sky for all time, which when scanned and decompressed by XYZ algorithm, will contain all the details to construct necessary technology to verify this theory against others]
OK, so it's a bit silly, but it has a very Biblical feel to it in its grandiosity ;) I'd probably settle for a persistent, personal appearance and several trips to the psychiatrist to prove I'm not crazy :-P
I think the main point is that for a supremely powerful being, this is nothing for it. Also, apart from myself, I know very many similar non-resistant/spiritually hopeful non-theists out there who would latch onto solid demonstrations like this (as opposed to trying to torture the data to conform to some more mundane materialist explanation).