I also have lots of issues with reinstalling broken Big Sur. The installer apparently needs to phone home to Apple to get permission to reinstall the OS, and th

I also have lots of issues with reinstalling broken Big Sur. The installer apparently needs to phone home to Apple to get permission to reinstall the OS, and this fails. When this doesn't fail, it doesn't get permission to write to nvram, so the OS reverts itself to previous version after reboot. I like Macs having iPad-like performance, but I don't like the boot process is so locked down that it reminds me this computer belongs to Apple, not me.