Duplicate junk folders in Big Sur Mail

How do I consolidate my Big Sur mail Junk folders?

Big Sur Mail handles trash & junk poorly

I want to quickly scan my junk, making sure that it is correct before deleting it.  But with Big Sur, I have trash and junk folders “On My Mac”, on “iCloud”, and on my other e-mail account.

I went to preferences and discovered that I could change my iCloud MailBox behaviors to go to trash and junk “On My Mac”, except that now I had two Trash folders and two Junk folders On My Mac.  Changing that setting back got rid of the “On My Mac” duplicates, but I still had duplicates elsewhere.

And I couldn’t change the behavior at all for my other e-mail account.

My old iMac couldn't run Big Sur, and my new iMac can't run anything but Big Sur.