Missing Trash Sub Folders

In Mail I have a Trash folder On My Mac. It used to have three sub-folders beneath it such as iCloud, and Midco (my provider). Well suddenly the sub-folders are gone. It may have been since I recently loaded BigSur, but I'm not sure. The problem is that all of my trashed emails are missing and I cannot find them. Are there any bugs in BigSur or what may be my issue? If I do a search for known missing emails in my 'All Mailboxes' mailbox it will find the missing emails and it will say in the header that they are in 'Trash - Midco'. That trash bin is nowhere to be found. How can I get my sub Trash mailboxes back?