The Dragonflight Dungeon event ends tomorrow which means you have one last day to benefit from the rewards! While usually the only major reward is the Heroic box from the quest, with the addition of the Megadungeon in Patch 10.1.5, the final boss Chrono-Lord Deios drops one more piece of loot.
If you don’t complete Hard Mode, you still get a total of 3 pieces of loot off the final boss but this loot can only be scaled to item level 441. If you complete Hard Mode this loot can scale to item level 447 and you get 3 pieces!
If you need Mirror of Fractured Tomorrows make sure to get your Dawn of the Infinites run this week as you have a much higher chance of getting the loot you want.
Hard Mode Immortal Dawn of the Infinites