What Happens to My Albums When I Leave Google Photos?
Albums become plain folders in your export, and album membership is not stored in the photos. Here is what survives and what does not.
Albums survive as folders, and that is all.
In your export, each album becomes a folder with the photos in it, plus a small metadata.json describing the album itself. That is the whole of it. There is no standard place inside a photo file to record "this belongs to the Italy 2019 album", so album membership does not travel inside your pictures. If you copy the photos out of the folders, the albums are gone.
Two other things to know. A photo in three albums may appear three times, once per folder, which inflates your file count and creates apparent duplicates. And shared albums only contain the photos you personally added, so they can look nearly empty.
Some destinations can rebuild albums from the folders. Immich and PhotoPrism both do a reasonable job, and immich-go reads the album metadata directly.
What you can make permanent is the date and the location, because those do have a standard home inside the file. The app writes them into every photo from the .json sidecars, so no matter which app you land in, your timeline and your map are correct. It can also keep or rebuild the folder structure as it goes. The first 500 photos are free.