When ever a sin Archbishop dies, their authority “will” make its way to Subaru. As is the case with sloth and greed. Stride who was the holder for pride is already ceased so won’t Subaru already have pride but just not know of its existence.
Secondly I think Subaru has pride rn is because “four of the seven jewels” lit up when in contact with its owner or Subaru. The Seven jewels= Seven sins? Who knows.
Thats is why this is just a theory, a fan theory