Recipe #11: 4 primal ancient items and 4000 Lost Souls = 1 Primal Soul Shard
Recipe #12: 1 Primal Soul Shard and any Ancient legendary = Primal Ancient of the same item with Random Stats
This would not break the uniqueness of Primals, players would still have to get 4 random junk primals and also farm 4000 forgotten souls for a random chance at a useful Primal item.