I have felt my question most likely lies in the realm of “unknown” at this point. So far, just having a question about the atonement has been a blessing for me personally, because I have been thinking about it more.
I’ve also thought that the answer may exist in the infinite nature of Christ’s atonement, as you have noted. So far, that feels like it comes the closest to anything that could be considered an answer.
btw, what is this penal substitution theory you spoke of?