...but if anybody else has any thoughts on my trash problem, please weigh in.
If you are on Mac, your default session is located in users/username/pictures/Capture One Library. If you click on that folder you should see 6 folders inside and one should be labelled "Trash."
As Jack has mentioned, Capture One has a default session and corresponding session Trash. I'm using a Mac as well so, I can't comment on where the default location for the default session Trash should be on the PC. Perhaps, the manual might say?
If you don't have this default Trash folder is it possible you may have deleted this by accident?
As well, each time you create a new session a trash folder should be created inside that session's folder.
In any event, if for whatever reason this is not happening then you might consider trying to manually set the Trash folder location:
• If your Trash folder has gone "missing" then first create a folder for trashed images in the relevant session folder (name it as you feel appropriate). Note, it's likely best to this in Capture One's Library tab.
• One can designate/set a folder as the Session Trash folder by control clicking (Mac keyboard shortcut) on the appropriate in Capture One's Library tab. Or by selecting that folder in the Library tab and choosing the File -> "Set as Session Trash Folder" menu item.
• Then give it a whirl on a test/trashable image.