I had the same issue on iOS 14.1 and Evernote 10.1, where the "send to" or "share to" option in some aplications ( banking app ) brought up the Evernote clipper, let put in a title and select the notebook, gives the message that "sync happens later"... but never happens.
I removed evernote now, rebooted the iPhone and reinstalled Evernote and works now ...