Got a fix for this issue if you have root. Just change your phone's model number to SM-G955F (S8 Plus). They already fixed it for the S8 Plus so the keyboard size is normal on all resolutions.
So 50% means 1440*0.5 * 2560*0.5? That's actually 1/4 of the resolution and pretty confusing. Anyway, Samsung's fault. You did a great job!! Works perfectly fine with my Galaxy S6 running Xtrestolite 2.4.
Yes.