Take 100% of the atoms that make you, shake them in all directions until nothing remains of their initial arrangement. We have the same collection of atoms, but is this paste made up to 70% H2O still you? Not really, is it?
Take 100% atoms similar to yours (but not yours), recruit Santa’s goblin troop, and arrange the atoms in exactly the same way as yours. Do you think the result is you? Yes, in all probability, since it is this process that takes place gradually in reality.
Biology, physiology, psychology, we are only relationships.
Your choice of the atom as the unalterable foundation of matter is moreover arbitrary. At the end of a year we have some carbon14 atoms which have definitely mutated. And 90% of our atoms will always be part of the same molecular radicals.