Help - five volumes and I only want one!

FYI. A "typical" macOS Big Sur drive should look like the following after you issue the command that BDAqua is suggesting:

Under macOS Big Sur, your Mac's internal SSD drive is formatted in APFS and would (by default) have a single Container (what used to be called a Partition) with, at least, five volumes:

• Macintosh HD & Macintosh HD - Data: These two volumes make up a Volume Group that is the macOS operating system (the first one), & some of the OS and your data (the second one.)
• Preboot
• Recovery
• VM

Ref: Boot disk layout on Intel and M1 Macs: High Sierra to Big Sur - The Eclectic Light Company

Your Mac's internal drive has, at least, two issues based on the Disk Utility image:

1. It has an additional Container (disk2), which shouldn't be there.
2. It appears that the Macintosh HD volume was renamed to "MacOS," and the Macintosh HD - Data volume was renamed as "USB." These are not necessarily an issue, but could be confusing.

Yes, you can delete the Container disk2.

APFS was designed to handle these sorts of tasks better than HFS+, and to do so without data loss. It seems to works very well in my experience.

I have just run the following exercise several times on my Catalina MBP 2012 . I did it with the APFS internal boot SSD and with an APFS external SSD, so I can confirm it works.

You will have to partition the device, but APFS can do that without wiping or otherwise damaging your other volumes and data. Judging by your Terminal screenshot, Container disk2 is empty and contains no volumes.

As a "just in case something goes wrong" step, you should be sure you have backed up you Mac before you do this.

• In Disk Utility, click the Container disk2, then click the Partition button in the toolbar. Then click the Partition button at the bottom of the descriptor window that appears.

• Select the Container disk2 partition in the pie graph window that appears, and click the minus ( – ) button below it. The pie graph will change to reflect what the result of the re-partition will be.

• If you are happy with the projected result, click the Apply button at the lower right of the window.

• Disk Utility will present a description of the proposed action and a confirmation button. If you are okay with the proposed change, click the Partition button.

Assuming all goes well, your device should now have a single container, with the five volumes and one snapshot (backup) that are already within it.

EDIT - as others have pointed out, the five volumes in one container are normal for macOS using APFS. And when you have complete this change, the storage space in your Mac drive should be consolidated normally.

Open Terminal & execute this command...

diskutil list

Then eport like this...

diskutil list

/dev/disk0 (internal, physical):

  #:            TYPE NAME          SIZE    IDENTIFIER

  0:   GUID_partition_scheme            *1.0 TB   disk0

  1:            EFI EFI           209.7 MB  disk0s1

  2:         Apple_APFS Container disk5     1000.0 GB disk0s2

/dev/disk1 (internal):

  #:            TYPE NAME          SIZE    IDENTIFIER

  0:   GUID_partition_scheme             28.0 GB  disk1

  1:            EFI EFI           314.6 MB  disk1s1

  2:         Apple_APFS Container disk5     27.6 GB  disk1s2

No you can't the Device/ Volume tree is the default of APFS formatted drives.

You can't do anything about it because you will ruin your macOS system.

Leave it alone.

Ok, it looks like I was correct about my assumptions of your macOS volume group. Why they were renamed, as such, I don't know. Most likely, it occurred during the installation, or reinstallation, of Big Sur.

Yes, Container 2 could be deleted using the steps provided by D.I. Johnson.

It is normal for an APFS formatted drive, Apples non vision of the future.