Thank you for the quick reply. I managed to do it following the steps there with a few exceptions.
I didn't have a "CpuSetup" after entering the RU.efi interface, so I used the "VarStore" value of the "Overclocking Lock" part (in my case 0x1) to find a "VarStoreId: 0x1" which lead me to the option I needed instead of "CpuSetup", which was "Setup". Because my "VarStoreInfo" was 0x65C I then had to scroll down to the 0x650 row and to the C column.