Photos from same date split between sub-folders

For the last 2 years it seems as though my photos have been split between folders and subfolders during import.  This means that within a series of images they are randomly split between 2 places (see screenshot of mac finder windosws). This seems to have happened afte selecting phtos for a year end calendar - although I have no recollection of trying to make new folders during this process.

When I correctly 'find' a photo using the navigator and re-link it, and then try to move the photo to be with the other photos in the same numbering I am not allowed as the "filename" already exists. I have circa 2800 photos in the wrong place across many dates of the last two years. Any thoughts on how to fix the navigator folder so its really by year;date with no subfolders ? and then of course get all of these photos back into the right place without having to search for each individual photo / folder and fix it ?

Is it easier to delete all of 2023/2024 and re-import - I lose all the eidts but not so many and the alternatove may take longer than me re-editing ..? Thanks for any suggestions.