I am having the same issue as skkippy when attempting to export a notebook with 707 notes.
I am running MacBook Pro Sonoma 14.1.2 and Evernote v10.71.2
First of all, there should be some feedback to the user on what exactly failed.
So I tried the method of exporting 100 notes at a time. All successful except for the fifth batch. I exported the failed batch in smaller chunks - the first 50 notes, then 25 of remaining, then 12 of remaining, then the last 13 and all were successful. No notes were opened/edited - only selected for export then moved to trash after successful export.
I did successfully export two other notebooks prior to this one, but they were smaller - less than 100 notes each.
Hope this helps.