So this is a Samsung Galaxy Fold 3 case with an optional add-on of an s-pen(fold edition) holder from the Flip cover case (Link below). The s-pen holder is quickly removable with a slide on hinge. Transfer of the s-pen holder from the case is a non-destructive slide on slide off.
Oh, and did I mention the built-in stand with two angles…
(https://www.samsung.com/us/mobile/mobile-accessories/phones/galaxy-z-fold3-5g-flip-cover-with-pen-black-ef-ff92pcbegus/)
The author marked this model as their own original creation.