US Gift/Estate/GST Taxes


So I realize this information has zero effect on the exam, but I’m just trying to understand this in the context of the US. So looking at the tax code, all of these things are essentially taxed the same which confused me, as I thought GST was put in place to stop the practice and would effectively be 2x the rate of the estate tax. So if I wanted to pass some amount of money onto grandchildren that is above $5.5m, would I be hit w/ the gift tax and the gst tax effectively creating the same result as paying the estate tax twice?

Thanks for any clarification here.