In the Samsung Galaxy Note 9's Gallery app, there isn't a separate Favorite Photos folder. Instead, a button on top of the albums page labeled Favorites opens up hearted photos.
The problem with this is my favorite/hearted photos don't appear as a separate folder in WhatsApp when I try to attach a photo. For example, I press the attach button, Gallery, and there is no separate folder for my hearted/favorite photos.
How to quickly access those photos?
You can reach you installed gallery from within WhatsApp by either longpressing the "gallery"-button within the attachement-menu or by clicking it, then clicking the three dots in the upper right corner.
Old Answer with the assumption, that you were asking for WhatsApp-Favorites:
The starred messages are no seperate folder in the gallery, but a list within WhatsApp.
To get to this list follow these steps:
1. Open WhatsApp.
2. Tap More options. (The three dots)
3. Tap "Starred messages".
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