Not sure where you are in your progression or how robust your 7* roster is but I would hold it for something that’s awakened and covers lots of ground. All these champs want their awakening. Even Warlock if you’re a BGs player.Edit-Iso-Fiend is fine if you already have better at r3 in mystic class (America, Kushala, Werewolf, etc.)
Juggs dup is helpful but not critical. Warlock also doesn’t need his. You also might want to save it for Deathless Thanos if you are chasing him and plan to do the Carina’s necropolis deathless challenge.