Can I Fix My Photo Dates Without Re-Downloading Google Takeout?
Yes, if you still have the .json files. They hold the dates. Here is how to check before you request a second export.
Yes, as long as you still have the .json files. Everything you need is already on your disk.
Look inside your export folder. If you see files ending in .json next to your photos, the dates and locations are there and nothing has to be downloaded again. A second Takeout run takes days and gives you exactly the same thing. The only reason to request another export is if you deleted the sidecars, or if parts of your download were incomplete.
Point the app at the folder you already have. It reads each sidecar, writes the real capture date and location into the photo, and tells you at the end which files had nothing to work with. Your first 500 photos are free, so you can confirm your export is usable before spending another week waiting on Google.