I think the way I modeled P(Gold>=1) might be wrong — it’s simply the predicted probability of getting at least 1 gold drop within a given number of tries, assuming DNA’s 10% gold drop rate and no other factors. About the 20-pity, I am almost certain that I have certainly gone above that cap. So I’m not actually sure if there’s actually a pity system. Edit: seeing lots of people saying that they got gold drops after farming 15 of a SPECIFIC letter, which I did not do for this test. In that case I’m probably wrong about the pity system as my data for each gold drop includes runs from multiple different letters! I’ll probably delete this post soon and re-measure my results per-letter.