Beetleback Chief goes more in a Goblin kindred strategy, which is fine, but not synergistic with the rest of the deck
Look at the composition of your deck and figure out what gives it that extra punching power
In the meantime, you can browse all the cards from the set and its Commander decks in the Magic: The Gathering FINAL FANTASY Card Image Gallery
Creatures (19) 3 Liliana, Heretical Healer 2 Kalitas, Traitor of Ghet 3 Indulgent Aristocrat 4 Asylum Visitor 4 Insolent Neonate 3 Nearheath Chaplain Lands (24) Spells (17) Im not sure if Nearheath Pilgrim is good enough to replace Lingering Souls, but Lingering Souls was way over-the-top, so Im willing to experiment with the toned-down version
Cards like Approach of the Second Sun or Maze's End usually see some play in decks aiming to break them
But as a payoff for the discard deck, I think this Belle is pretty good