I think it would be a great addition to rembg to allow the user to separate important parts of the object and save them. I found Meta Segment Anything Model 2 (SAM 2). This is a second improved version of SegmentAnything Model (SAM), which also works for video files.. It is pre-trained - you can point with the mouse or enclose certain regions and it will segment them for you and then save it.
Demo site (SAM) for test https://segment-anything.com/demo#