I am using 2023 version of Illustrator. I am opening a file created a year ago. It opens and it is blank, although when I hover over the page with my mouse up comes a blank box with the blue outline and X in the middle. I get this message when I am trying to open it; Could not find the linked file.....Choose Replace to select another file or Ignore to leave the link unchanged. So I close that file and then I can see my old file in the recent files list with the images and text.
The representation in the Recent Files area is a low-res preview that was saved with the document the last time it was saved a year ago. It does not reflect the current state of the document, because, as you've noticed, a placed file has has lost its link, either because that file have been deleted, moved or otherwise gone astray from its previous location. The correct thing to do when presented with that message is to "Replace" to relink to the existing placed file. (It really should say Replace/Relink but that's nitpicking). Even if you click Ignore (which doesn't solve anything as the link is still "missing", as evident by the Links panel, where it will be flagged in red), you can relink at this point as well.