I recently encountered something similar on my M1 air when i tried to erase it (if you got a new m1 air don't do it it's not really necessary). So turns out, wi

I recently encountered something similar on my M1 air when i tried to erase it (if you got a new m1 air don't do it it's not really necessary). So turns out, with I believe Catalina, APFS has a system partition and a data partition on an m1 mac. one is read only with SIP on. I don't know how exactly APFS stores snapshots but the read only is for snapshots + macos updates sort of like iOS. If you erase the mac (btw there is an erase mac option like in iOS in recovery if you don't know decryption key so manually doing it is unnecessary) then your mac will basically clean your drive and reinstall macOS to the latest version. Now once you do that the read only partition is basically a dynamic container and remaining software is in the partition called untitled. This is similar but here the partition scheme messes up a little. You can delete local snapshots if you use time machine to free up space but the system snapshots (not the back up ones this is something different to protect system integrity) stay. If you really want to erase an M1 mac do it using the configurator which btw people have claimed has bugs so maybe wait. But otherwise this is going to be like iOS so you can just keep using your mac with delta updates because your system partition is going to be read only with snapshots for any failed updates called macos - System while all your data will be in macos - data. This 'erasing / formatting' a computer is reminiscent of Windows experience. It's just easier to clean everything and start again. But ideally it shouldn't be needed for Apple silicon macs (once macos bugs are sorted ofcourse).