Been having this issue for a long time and can't seem to find the answers. While in Render View any material value slider adding nodes/removing etc blender will freeze and viewport goes grey while it thinks about what you just changed then will display your result, the freeze is usually about 5-10sec depending on the scene... to wait 5-10 sec every time you touch something is insane. Once in a while I'll watch a tutorial on something and amazed at how responsive the viewport is while shading in render view.
I am on a 2019 Mac Pro, AMD Radeon Pro W6800X Duo., 96gb ram. Any help would be appreciated.