Why Do All My Photos Have the Same Date After a Takeout Export?
Every photo shows the day you downloaded the export. That is your computer guessing, because Google left the date out of the file. Here is the fix.
Because that date is not your photo's date. It is the moment the file landed on your disk.
When a picture has no capture date inside it, your file manager has nothing to show you, so it shows the file's created or modified time instead. Every photo in your export was created on your disk within the same hour, so every photo gets the same stamp. Ten years of memories collapse into one afternoon. Sorting by date becomes useless, and any app you import into inherits the mess.
The real dates were never lost. Google put them in the .json files beside your photos rather than inside them. Until something copies them across, your computer keeps guessing.
This is the easy fix, and it takes one run. The app reads each sidecar, writes the true capture date into the photo, and corrects the file timestamps so your folders sort properly again. Try it free on your first 500 photos and check a few by hand before you go further.