Samsung should make a stylus for the S+ or FE series as well, for uses who don't like the large form factor of the ultra, similar to the Note days. Screen size should be between 6.4-6.6
There was never a stylus for the S+ or S FE devices during the note era. The reason it is restricted is because the Wacom digitizing layer ads cost, thickness and complexity to the screen, as well as a per device licensing cost to Wacom. There's a reason that notes/ultras have always been so expensive.
