Is It Safe to Delete My Google Photos After Exporting?
Not until the export is unpacked, fixed, checked and backed up. Here is the order that avoids losing anything.
Not yet. An export is not a backup until you have opened it and looked.
Work through this before deleting anything. Unzip every part and confirm the photo count roughly matches what Google Photos showed. Check the awkward cases: shared albums only contain the photos you added, so those can look empty. Fix the metadata, because a library where every photo says today is not a library you can use. Look at the result on photos you actually remember. Back it up somewhere that is not the same disk.
Only then is Google holding a second copy rather than the only one.
The middle step is the one people skip, and it is the one that decides whether your archive is worth keeping. The app writes the real date and location into every photo, and lists anything it could not handle so you know the state of things before you delete. The first 500 photos are free.