I just bought this app to set the refresh rate at 96 hz on my note 20 ultra. I can see some positive effect on the battery. There is almost no discernible difference between 96 and 120 hz. It also has a net speed monitor which shows real time speed on status bar. And no, I didn't do the adb thingy it was telling me to do. Though you could do much more by doing that. Right now, I am satisfied with 96 hz and net speed monitor.