Do not touch EXIF ​​data

In preview on the Mac you can use:

Using Preview (Simple Edits)

1. Open the image in Preview.
2. Go to Tools > Show Inspector (or press Command + I).
3. Click the EXIF tab to view data like Camera Model, Lens, etc.
4. You can often edit the Description, Keywords, or add GPS data here directly, which modifies the EXIF, but be careful with date fields as they might behave unexpectedly.
   
   This is no batch editing. There are apps in the App Store.

Hi street79 and Happy New Year to you too!

TLDR: Flatten and save, don't export.

The following remarks are macOS-specific - I don't know how it works in Windows.

macOS Finder displays the file creation and modification dates (macOS filesystem metadata), not the image creation and modification dates (EXIF image metadata).

And what you want is for the file creation date to match the image creation date.

However, when you export the document as a .jpg, you are creating a new file in the file system, and the Date Created and Date Modified you see in macOS Finder reflect the attributes of the new file. There's nothing you can do in Affinity to change this behaviour, or match them to the date of the image. And as far as I'm aware, Finder windows can't display the original dates of images.

In Affinity, if you re-open modified files and display the Metadata panel, you'll see that the Date Shot still reflects exactly that: the date that the original image was created. But this will only work if you export the original metadata - if you uncheck Embed Metadata in the Export dialog, this information will be lost. ExifTool (see below) also reports the image's original date and time in the new file.

One way round it is not to export a new jpg, but to update the original file by flattening it (In Affinity 3 Pixel Studio and Affinity Photo 2, go to the Document menu, choose Flatten) and then File>Save (not File>Save As...). This will remove all the edit history, layers, adjustments etc from the working document, but because you're not creating a new file, the information displayed in macOS Finder will retain the file's original Date Created.

However, the file's Date Modified in Finder will change to reflect the date and time that you last saved it. Again, this is part of the way the file system works, and not related to the EXIF metadata.

Another way is to use a dedicated EXIF editor like ExifTool to modify the file system metadata by setting the file creation date to be the same as the original creation date. ExifTool is a command-line tool (available for both macOS and Windows) and has an extremely steep learning curve. If you're not used to coding, it's not the best place to start learning And even in ExifTool, modifying file creation dates in macOS requires the installation of additional Developer tools that aren't available in standard builds of macOS. So that particular method is not for the faint-hearted.

You could also look at some of the results from a Google search for macOS modify file date, but again you're going to be into the realms of Terminal and the command line.

Hope this makes sense!

There is a bug in Windows 10.
"Created" and "Modified" dates are switched. File can't be modified before it is created.
Well, this is Microsoft and everything is possible.