We think this is both real and will come in at least two different screen sizes, though ETA is very unclear.
Two anecdotal data points that support this.
One Samsung has already filed what is the equivalent in South Korea for trademarks and copyright stuff with this name.
Two Samsung has started telling some of their customers that 15.6 inches or so is the maximum size display that customer will buy in a clamshell or 2 in 1 form factor, but OTOH there is considerable demand for larger screen S-Pen capable devices.
There is a slight chance that Samsung might mention something about these at the upcoming Unpacked event, but our sources think it’s a lot more likely to come later in the year at a dedicated “Fold” event where they will also announce the follow ups to the Flip and Fold 3
Samsung’s Galaxy Book Fold laptop with a foldable display might launch soon (bgr.com)