How do I delete photos from Apple Photos retaining only those marked as favorite?

Question

This should be a fairly easy task to carry out, but I cannot seem to figure out a straightforward way of deleting all but favorite photos from the Apple photos app. One workaround is for me to create a smart album to pool all favorites together --> export --> delete all photos --> reimport, but this definitely is a waste of time especially with large libraries.
Am I missing something here? Any ideas?

Answer 1

You can do this using smart albums.
Unfortunately the gif I made to show this is to big so pictures will have to do.

1. go to all your photos and select all of them (cmd+a).
   
2. Create a new smart album for your selection
   
3. In the popup select photo is not favorite as filter, you should see the number of matches.
   
4. In the smart album are all your photos not marked as favorite, select them all (cmd+a) and delete them (cmd+backspace).
5. Go to all your photos, only the favorites remain.
6. Empty the trash in the photos app to remove all deleted non favorites.

Answer 2

Found somewhere else a better-yet solution; you can even include in the filter photos that are in an album (but not favorited) too.

1. Go to every album you want to stay after mass deletion (including the favorites album)
2. Select all pictures in said albums, click hide
3. Go to camera roll and delete all pictures
4. Go to hidden smart album and unhide them

Ta-Da. Works like magic, and order between pictures is kept. I'm just so happy to have found this user suggestion somewhere else; had this frustration for many years.