Smartobjekte einzeln austauschen, nicht alle auf einmal

It sound like your smart objects were mad used layer duplicate so they share a single smart object. The three layers share the same object but each has a different associated transform so each smart object layer positions the object in a different location over the canvas,

If you want independent smart object layers the layers need to have different objects.  If you want to start with a copy  you would make that copy using menu Layer>Smart Objects>New Smart Object Layer via Copy

If I understand correctly, it sounds like you have 3 smart objects but when you make a change to 1, the other 2 don't change. The process you use to make the copies of the smart object matters. If you want all 3 smart objects to change at the same time when you open 1 and make a change, here's how the template should be made:

1. Make a layer

2. Right-click and select Convert to Smart Object

3. Make 2 copies of the smart object layer

Then you can double-click on any of those smart objects, change the contents, save, and have the change take effect in all 3 smart objects. They all reference the same psb, so when you make the change there, the other layers are also referencing it.

If you make copies of a layer and then convert each of those to a smart object, they will each reference a different psb. So making a change to one won't affect the others.

Likewise, if you make a smart object, right-click, and select Make New Smart Object via Copy, you're making different psb. And making a change won't affect the others.

I hope that helps.