Thank you for responding! I appreciate the help and input a lot.
I did log in via Evernote.com, and they're missing from there as well. Previously, the notes were in "Notebook stack [1]," but that's gone from both my connected devices.
Fortunately, I have a laptop with a messed up wifi connection which went offline in late June, and when I turned it on and accessed Evernote online, the conflicting changes notebook and notes (41 of them!) were there in the same place as before, which was a relief.
Based on the fact that the size of my backup files drops by almost exactly the same size as the saved "conflicting changes" notes from the offline laptop, I'm pretty sure the folder disappeared when I updated evernote last, which I think I've seen at least one other person on a forum thread report as well.
I back up notes pretty frequently, so as long as the backup includes the conflicting changes section, I guess I'm safe up to whenever my last backup was. My main issue is knowing which notes in the "imported notes" section were the ones that were in "conflicting changes" previously, but since I'm ultimately intending to merge all the notes together anyway so as not to miss anything, it doesn't matter (as long as they're there!!).
Is there any way to tell which notes in the imported folder came from conflicting changes originally? I'm possibly just being super dumb and unable to think of it.
Thank you again for responding, and sorry that it took me a while to answer!