Exemplary triune jewelry may be obtained by completing daily board quests in Cyrodiil.(...) Do Exemplery Triune rings ever drop from the dailies? (...)
I have never had Exemplary Triune Jewelry drop for me and didn't even realize they could, though TTC says they exist. I would suggest buying Dawn-Prism stones with with AP from BG or Cyro merchants. They cost 100,000 which you can farm pretty quickly from an active day in Cyro or ten-or-so BGs. Failing that, there is a 150k AP daily login reward coming, or you could buy the stone itself from a guild store for cheaper than the research jewelry. Then ask a guildie or random master crafter to make it for you. Or I could since you mentioned playing on PC NA (@Oterwitz).
And PS aren't AD winning Ravenwatch and Blackreach by a ton?