The "Recents" folder in my iPhone seems to contain every photo I've ever taken, not strictly 'recent' ones. Where is the setting that determines how far back in time this folder goes to stay in recent vs. getting moved into "All Photos?"
The Recents album is a generated view of all photos and videos by each’s date added to the library.
This is in contrast to the All Photos view which is always in date captured order.
For example, if someone uses AirDrop to send you a photo they took on their phone, the photo will appear at the bottom of Recents but in the right date position for when it was taken in All Photos.
This cannot be customised. Usually, use the All Photos view, unless you’re specifically looking for media by when it was transferred.