That's because there aren't really any truly "unblockable" attacks, only attacks you don't have the stamina to block or that your shield doesn't resist.
Out of curiosity, as I am not using a shield this run. Big area attacks that make the ground rise up and often fling you into the air. Do shields block those?
Also I think technically the cipher pata is unblockable. But that’s more a pvp thing.