Free space is taking up 927 GB after deleting Windows 10 Bootcamp

AFAIK - there is only one Safe Way to Remove a Bootcamp " Windows Partition "

Remove Windows from your Mac using Boot Camp - Apple Support (CA)

If this method was not used, you may need to Wipe the Entire Drive 100% Clean an start again

Using the Command Option r ( there keyboard Combo ) to connect to the Internet Recovery Mode

It will present options >> Disk Utilities >> View >> View ALL attached Drives. 

Choose the Upper Most Drive ( not the volumes indented and list below ).

The drive normally is called Apple Media or Apple SSD - that is the drive to Erase and format as APFS

Once that is done >> backup out of Disk Utilities and choose install macOS. 

The other longer way

This method will WIPE ALL Data and there is No DATA Recovery - Period.

>> Only works on Intel Based Apple Computer <<

To perform this action will require booting from a Bootable Installer. 

The Bootable Installer can Only be performed on an Apple Computer 

This will have to be performed from a Qualifying Computer to run the version of macOS to be made on the Bootable Installer. Example : Bootable Installer of Big Sur would have to be done on a computer that Qualifies to run Big Sur.

Notation: If the computer being used to perform this action is Too New or Too Old to qualify to run the version of macOS - this computer can not be used.

Alternative is, to gain access to a Qualifying Apple Computer from a family member, friend or associate.

Extra Special Notation regarding the Touch ID equipped Apple Computer.

 About Startup Security Utility and Must Enable from Recovery Mode the ability to boot from External Drive Before Attempting 

1 - Shutdown computer and disconnect all external drive Except the newly created Bootable Installer.

2- Restart and immediately hold the OPTION key until the Startup Manager appears and choose the USB Drive. 

3 - It will present options >> Disk Utilities >> View >> View ALL attached Drives. 

4 - Choose the Upper Most Drive ( not the volumes indented and list below ).

5 - The drive normally is called Apple Media or Apple SSD - that is the drive to Erase and format as APFS with the GUID Partition Map.

6 - Once that is done >> backup out of Disk Utilities and choose install macOS. 

7 - Follow the prompts and it may automatically reboot several time. 

8 - Upon a final reboot - Setup Assist will present with the newer version of macOS.

sorichard wrote:

What do I do with the ApplrAPFSMedia?

This in not intended to be an off-handed reply please believe me it is Not.

Have done a Search of this website posting

The Only reference to " ApplrAPFSMedia? " is appearing in you above reply question

If you believe this is a Volume, Container or Partition on this drive ?

It too would be removed via the Scorch Earth Method and / or the previous Internet Recovery Mode outlined earlier