Luck system

Once i saw someone in yt comments saying that its based on simple luck and not the multipliers, and i been with this in my mind until now. I can say i am very unlucky, i made more than 150 sukunas, more than 70 tojis and a LOT of other bosses and investigations, and i only have 4 special items from them. so i was doing missions to teleport to each place and do their daily quests, and didnt even use nothing, and when opening the second chest, the thought of simple luck went through my mind, i once had a 4x multiplier luck on a nightmare sukuna and had all rares, and so when i opened this chest, and got vengeance, just when i was about to get ir for 180 keys in the market, and i realized this game is broken