Erased Hard Drive - Still have 300 GB in "Other"

If one wishes a True Clean install of Big Sur - or for that matter any macOS - How to create a bootable installer for macOS. Understand the method being suggested here is wiping the Drive 100% Clean of everything - can not be recovered. Boot to the USB Installer via Option key immediately at startup. Notation - if the computer has the T2 Secure Enclave ( Touch ID ) read here first as you have to boot to Recovery Mode - Command + r - and change Secure Boot options to allow booting from External Drive and other setting in Secure Boot. Now, once booted to Install Big Sur - get to Disk Utilities and View >> View All Attached Drives >> choose the Upper Most Drive ( not Volumes listed below ) usually called Apple SSD and Erase this Drive as APFS with GUID Partition Map. This wipe everything from the drive. Now back out of Disk Utilities and choose Install macOS and follow the prompts until Setup Assist for Big Sur is presented.

Special Notation regarding the Newest M1 CPU from Apple - https://support.apple.com/en-us/HT211983

Hi Richard,

‘other’ represents the pre installed settings such as the apps that come on the computer etc. i don’t believe there’s much you can do about that. i’ve run into a similar issue in the past.