You can just set the IR to 6x in the global OpenGL ini file without having to do it individually for each game. In your Documents folder, under Dolphin Emulator/config/ there's a file called gfx_opengl.ini Under [Settings] adding EFBScale = 9 should enable 6x IR in every game which doesn't have a different value set in its ini.
OS: Windows 10 64 bit Professional
CPU: AMD Ryzen 5900X
RAM: 16GB
GPU: Radeon Vega 56
CPU: AMD Ryzen 5900X
RAM: 16GB
GPU: Radeon Vega 56
