/execute as @e[type=item,name=金块,rx=0,rxm=0] at @s run loot spawn ~~~ loot "chests/end_city_treasure"

/kill @e[type=item,name=金块]

在这个指令里，要用循环完保持开启。第二个是连锁保持开启，金块儿就变成了幸运方块儿