Of course it depends on the measurements of your countertop area but, yes, all seems are visible in stone. The only truly "seamless" application is in solid surface materials such as Corian as it is an acrylic.
Dekton will have seams but they should be less than the industry standard of 1/8".

Also, we wanted to note that when Dekton is mitered on the front edge for colors like Aura, you will see a pinstripe where the joint on edge is. Attached is a photo example of what I'm describing.

Good luck with your project!