Hi, When putting 1.0 in dropchance the objects drop randomly, it doesn't matter if I put 0 or 1.0:(
I am doing something wrong? or is it a mistake:/

Works fine for me on 1.16.5.
The order of drops is Feet, Legs, Chest, Head
Personally I use 1 0 0 0 all the time, and the feet slot item always drops.

Also one more thing to note is that even if you give an item a drop chance of 0, the looting enchantment is additive meaning it will drop rarely if the player uses a looting sword. If you don't want this to happen, curse of vanishing is the best alternative.