You will not be able to perfectly match RTD with Powder as they have different ingredients and different manufacturing processes.
the only way you will get close is to use a VERY high power blender AND let the shake sit for a while in the refrigerator for all the powder to be fully absorbed by the liquid. there are many other tricks and tips on other threads about this that can also help with the smoothness such as replacing part of the water with milk, using ice in the blender etc.