Unable to read or delete small containers within iMac's SSD

That looks like an iMac with a split Fusion Drive, and the SSD and the hard disk drive (HDD) parts each set up as APFS volumes.

I’d expect the tiny Apple SSD and the WD 4 TB HDD to be combined together into a Fusion Drive, and this Fusion looks to have been split. Possibly by an HDD replacement.

I would not suggest trying to re-partition an APFS volume at this juncture.

Here is: How to fix a split Fusion Drive - Apple Support

Have a complete and current backup of all of your data on all internal storage before making any changes.

Provide a screenshot of the Disk Utility window as follows:

How to take a screenshot on your Mac 

(⌘⬆︎3) Command-Shift-3         Capture the screen to a file

(⌘⬆︎⌃3) Command-Shift-Control-3 Capture the screen to the Clipboard

(⌘⬆︎4) Command-Shift-4         Capture a selection to a file

(⌘⬆︎⌃4) Command-Shift-Control-4 Capture a selection to the Clipboard

(⌘⬆︎5) Command-Shift-5         Invoke new screen grabber

⌘ = Command

⌃ = Option

⬆︎ = Shift

I agree with John that it doesn't look like your Mac's boot drive.

Those containers are not on your iMac.

Those photographs are difficult to read and omit important details. Screenshots would be better. To learn how to capture, edit (if necessary) and upload screenshots to this site refer to the Appendix in Writing an effective Apple Support Communities question - Apple Community. Refer to Screenshots (Mac).

From the information you posted I can find absolutely nothing amiss with your Mac. If you are having trouble with it, please explain.