I want help about dual wield,dash and blink

I want to make my own rpg series but i have promblem about this 1.dual wield i ever see people use fishing in offhand for offhand swing but i dont know how to do it and i dont know is have something easy than in new version 2.dash i ever see make protectile for caculate for new vector but player cant modify nbt 3.blink yeah i know is have tp but i want how to check block in front player (i dont want to use ender pearl)