Diamond ore bug

Either I am extremely unlucky, or this is a bug. I mined about 50,000 blocks each in the y coordinates 11 to 13 in 3 different worlds and I could not find a single diamond ore (1.15 & 1.16 beta). If this is a bug please fix it because I even found all the other ores on the way (even emeralds). If this is a bug, please fix this because diamonds are an essential part of minecraft.