Boot disk volume layout is intricate in Big Sur. M1 Macs lose the EFI partition on their internal SSDs and gain two more for APFS. Contents of /System/Volumes has also changed.
What you need to know about disk formatting using the GUID Partition Table (GPT) to understand its problems and how to repair it.
They’re almost everywhere now: UUIDs and GUIDs identify disk volumes, printers, even the processes running on your Mac. Here’s an explanation.