I'm working on creating graphic layouts. And I got into trouble with a large .ai file. Mostly I work in Illustrator, but the recent move from the main place of work made me use cheaper software equivalents. Almost before the order was sent to the client, an incorrect filter overlay occurred, and now objects with an expanded scale appear when the file is opened. I can not edit it, either. there are still big mistakes. I really hope that you will not have to redo the work .
Have you considered making sure that the filter overlay that was created is not a linked file now? If it is, try embedding the file. This may allow you have an editable file.
if you are seeing a preview of the image when you open in Illustrator then hopefully all is not lost.
Look at the file in outline mode and if you just see a black square, then hopefully if you embed the file it will release, and allow you to make edits.