Hindi naman talaga, "Obviously" na gagana yan.
Dahil hindi ka naman nag-ininstall ng Official ROM at hindi rin naman pwede ng Stock Recovery para i-push ng SuperSU.zip.
Whether via "Install Via ZIP" or "Install Via Sideload", doesn't work like that.
I suggest, get your Scatter File by Downloading your Stock Rom from your Device or Backup your ROM Instead using NCK Crãck Tool. Para makuha ng tamang Mount Points and Makapag-bulid your Own TWRP.
I suggest get TWRP Auto-Port Installer sa Hovatek Forum*, and lagay mo ng mount points or hex code kada hex sa laman ng scatter file at meron ka nang twrp recovery.
Magegets mo rin. I Guess.

(* I-Search Mo na lang.)