While I've gotten all of the other relic weapons for my main, NIN, I am unlikely to ever do Eureka—the content just doesn't appeal to me as a casual activity. The two big turn offs for me:
  • There are no quests to track what you're meant to be doing. I dipped my toe into Eureka a while back, but since there's no questline tracking progress, I'm not sure what I was doing or what I should be doing if I tried it again.
  • Looking ahead, needing to join a discord or use a tracker for rare mobs and such is just more effort than I'm interested in putting into this.
Getting all of the other relics in the game was fine—it was either a casual grind that I could slowly do whenever or current content (I joined during ShB). Eureka just doesn't seem to fit the mold of something I can do as chill, low-impact content when I don't feel like doing anything else.

I'm not suggesting that Eureka needs to change or anything like that—I'm just saying that I'm not likely to ever do it, which is fine.