How the hell do people not have enough essence? We spend a lot of time doing fates, which give us fragments, to level our rank until 15. The quests story also give fragments as rewards. And then we need to do CLL x15 (before buff), which also showers us with fragments, based in how many prisoners we save. The next step is DR, and it also give us more fragments (though pretty rare).

What you got from CLL and those fates are enough for a x15 DR runs. Even after CLL buff (which means you only need to run CLL x3 for each relic), each CLL runs give 2/3 per fragments.

So yeah, you will only run out of essence if you sell all of them on MB.