OP Loot Datapack Dysfunctional

Hey
I've recently downloaded a datapack by Sire Solo that makes end stone drop OP loot. When testing it on a server (fabric 1.21.7), the end stone doesn't drop anything. I don't know what the problem is so I am just stuck. Not sure how any of you could help exactly, since I wouldn't know where to look for issues (I'm a beginner at this datapack stuff), but any help would be appreciated.