Run using Bash:
sudo mkdir -p /Library/Managed\ Preferences
cat << EOF | sudo tee /Library/Managed\ Preferences/com.brave.Browser.plist
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>BraveAIChatEnabled</key>
<false/>
<key>BraveRewardsDisabled</key>
<true/>
<key>BraveVPNDisabled</key>
<true/>
<key>BraveWalletDisabled</key>
<true/>
<key>TorDisabled</key>
<true/>
<key>BraveLeoEnabled</key>
<false/>
<key>BraveChatEnabled</key>
<false/>
<key>BraveAIEnabled</key>
<false/>
<key>CryptoWalletEnabled</key>
<false/>
</dict>
</plist>
EOF
Prevent the file from being modified:
sudo chflags schg /Library/Managed\ Preferences/com.brave.Browser.plist