Updating the version OpenCore you are using doesn't fix the 'Unkown' CPU error.
You need to add the latest release of RestrictEvents.kext to your /EFI/OC/Kexts folder with a corresponding entry for the kext in your config.plist.
Then you need to use the NVRAM > Add and Delete option to set your system CPU with the correct name.
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Here is an example of the RestrictEvents.kext NVRAM entries for my AMD CPU.
View attachment 15816 RestrictEvent Entries in Add & Delete NVRAM sections highlighted.
Obviously you would need to change the CPU name to match your CPU.