Set the "Unknown" processor kind for "About This Mac", depending on your preference. This is just a decoration.
Get the script and give it executable permissions:
curl -o cosmetiCPUKind.sh -fsSL https://raw.githubusercontent.com/Fansaly/CosmetiCPUKind/master/cosmetiCPUKind.sh
chmod +x cosmetiCPUKind.sh
Get CPU brand in macOS and set it:
sudo ./cosmetiCPUKind.sh
Custom CPU Kind:
sudo ./cosmetiCPUKind.sh -u "Intel Core iX-9900X"
Reset:
sudo ./cosmetiCPUKind.sh -r