Custom Wynncraft Textures/Models?

Is there a way to add custom textures/models for items in later versions of the game? Olinus' video was from 4 years ago and showed this but it used a mod that only goes to 1.21.1. I've also tried getting the full wynncraft texture pack, copying it, and editing but it would not let me make changes, or the texturepack would fail to load entirely.