Since you are drawing a mesh/model there’s some extra tricks to transparency. I’m honestly not sure what the “correct” approach is, but you can try discarding pixels with an alpha value below a threshold, instead of setting alpha to 0. Here’s me doing the same in a noise shader:
I’m sure @jhonny.goransson , @Dragosha, @astrochili or someone else playing with 3D stuff can tell what the correct approach is 