You have two accounts, they are not duplicated as they have different unread message counts. You also have a local folders account. An integral part of Thunderbird for storing mail on the local machine.

So what is it your really trying to do? Are the mail account IMAP or POP?

As you can see on the screen shot, there are two folders for certain items. For example, there are two folders INBOX and two for TRASH under the first account, and duplicate folders in the second account, too. (I don't know why but I don't care.)

I want to delete the duplicates.

I don't know where these stray folders come from. It's a rare fault that is occasionally seen in Thunderbird.

I don't think they are simple duplicates. They have different message counts. I wonder if the second instances in the first account are actually views of the corresponding folders in the second account. Have you ever tried to move folders from one account to the other?

I'm loathe to suggest deleting anything in Thunderbird, because if one is a clone of the other, deleting either may remove both.

I'd inspect the profile folder and look for genuine instances of duplicated folders there.

I'm sorry to say that I think your best action would be to start over with a new clean profile. If your messages are stored on IMAP servers then this should not require very much work. Material stored in Local Folders is more of a headache, but you could import specific mail folders from the old profile to the new. Look at the ImportExportTools add-on for this.