Something is epistemically justified if, as you said, it has some sort of reality to it not by coincidence but because the rule reliably shows what is real. I am trying to find a framework with some sort of reality to it, and that requires dealing with scepticism.
If you don't believe in reality in the first place how could you check whether something has reality?
You need to look at reality to check whether something is real. There no way around it. Your idea for justification has no solid basis in reality if you don't believe in it in the first place.
You don't get to be certain about justification and be skeptic about reality. There are certain types of Buddhism who you could call skeptic about reality but they would also not accept the concept of justification in which you happen to believe.
I've raised arguments for philosophical scepticism before, which have mostly been argued against in a Popper-esque manner of arguing that even if we don't know anything with certainty, we can have legitimate knowledge on probabilities.
The problem with this, however, is how you answer a sceptic about the notion of probability having a correlation with reality. Probability depends upon axioms of probability- how are said axioms to be justified? It can't be by definition, or it has no correlation to reality.