From what was mentioned in live letter looks like there will be actually 2 separate paths of upgrading relics, "eureka-esque" option and "anima-esque" option, so yeah grinding through the new exploration zone or if that is not to your liking old grind of like fates and dungeons. Personally think the new story seems way more interesting than what eureka had, prolly could of waited till 5.35 to start off things, but guess they just needed something for this patch which felt pretty empty already.