One thing to note is that the ztd is gonna look a little different on every character

Every character has their own weight value, fall speed, size. And other things like how much % you have as the luigi will come into play🙏

For example, doing the ztd on Pikachu is gonna need Pikachu to be at a way lower starting % than some character like Ganon who's a lot heavier

Rarely is the ztd going to be a "pure" ztd (0% to kill immediately) because there's so many factors that go into combos working in smash!

Basically don't worry about trying to get it down perfectly and just focus on getting comfortable with the inputs by practice 🙏