Cannot delete empty folders

I'm asking because this is in Catalina, and nothing has been posted for that OS.

I have folders that I have repeatedly tried to delete. The folder goes into the trash and then reappears in the Finder after about 3 seconds.

They are empty; nothing is using them.

They are not locked.

There are no permissions.

There is no error message.

It makes me crazy to have these empty folders because the actual data is on external hard drives (which are not always connected when this happens) and to click on a folder and find it empty sometimes causes heart failure. Also, I'm a neat freak and my disk keeps filling up, so I'm trying to streamline what I see on the disk.