The File creation date you are seeing in the Finder has nothing to do with the date, when the photo has been taken. If you sort by the Date Created, you will just see, when the file has been downloaded to you Mac. The filenames should be giving you the better chronological sort order. The image files imported from my iPhone 11 Pro Max are all strictly named ascending, like this (shown in Photos for Mac):

You need to look at the photos with a software, that can you show the capture date EXIF tag embedded in your image files.
The Photos.app can show you the actual capture date and sort by the date the photos have been taken, or you can see the capture date in the Finder, when you look at your photos in column view, or in Preview, in the Inspector.
The gaps in the numbers you are seeing may be from two different image series from different cameras. How did you transfer the photos to your computer? Are you sing iCloud Photos on your iPhone?