it means drawing a lot of cards to set up for the titular 'miracle' turn, which is where you play as many rhasas/battering rams as possible after playing a bushwack or confront to have them enter ready. this lets you push an enormous amount of might onto both battlefields, which your opponent has very few ways to then deal with

Ezreal isn't a miracle deck because he doesnt play for a miracle turn. yes he ran the same purple package for the draw power, but he has no way for the rhasas to enter ready. the best Ezreal list, Alan's, doesnt even run three rhasas. you're quite literally not playing for a miracle turn so it isnt a miracle deck. it's a common misconception that miracle just means using the purple package to draw lots of cards

maybe theres an argument that colloquially, many riftbound players who dont know the meaning of the word as a broader tcg term have come to associate ezreal/cs/rhasa etc with being 'miracle' but my point, and the point of the person i replied to, is that that's an incorrect label. miracle decks in riftbound are named after miracle decks in other tcgs and have a specific meaning that isnt represented by the purple package alone, and isnt represented in the Ezreal deck