Materials have black dots/shades, making it buggy

Hello everyone,
I have a problem with my material and I can’t seem to find a solution.

I am using a texture object with a masked blend mode so that only the red lines are visible, but black dots/shades appear when turning around the material , which makes it difficult to see in the world and looks ugly.

Unticking ‘Two Sided’ makes it a bit smoother, but doesn’t solve the problem.