MacOS Catalina 10.15.7 is causing a Kernal Panic - Forced an update to T2 chip by installing Big Sur - My machine is now bricked
You should use the Configurator to restore the T2 chip. Follow the steps shown here:
Apple Support: https://support.apple.com/guide/apple-configurator-2/revive-or-restore-mac-firmware-apdebea5be51/mac