If Conqueror had sunk Belgrano's escorts

Could HMS Conqueror have sunk both of General Belgrano's escorts, and what would that mean?

Yes; it would have destroyed a major portion of the Argentine fleet and made the loss considerably worse.

HMS Conqueror had the tactical ability to continue attacking General Belgrano's escorts. Destroying the entire group would have removed the cruiser and two more Argentine warships in a single action. That concentration represented a substantial share of Argentina's usable surface fleet. The result would therefore have been much more damaging than the already serious loss of Belgrano alone.