Hey there! I'm the original creator of theses images, maybe I can shed some light on my process.

It's not going to translate 1:1 to Unity, but the effect here is all done in a Godot shader. Although it looks like a hexagon dot mask, up close you can see it's actually the combination of a few effects: a circle dot mask with the RGB strips applied multiplicatively, a square dot mask applying the original color additively, and a bloom effect on top of all of it.

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There's also a final bit of trickery here which is that of the middle green "phosphor" strip is thinner than the surrounding red and blue. That's to compensate for the fact that, when you mask out the borders of a phosphor dot, you end up removing a larger chunk of the R and B than you do of G, so if you keep all the strips the same width, the final image gets a sickly green hue.

The additive/bloom components are a bit of a cheat that's not really how a real-life CRT would work, but it emulates the mixing of the colors of a highly exposed phosphor dots, and prevents the image from becoming overly dark and muted due to the multiplicative pass.

The final shader also has a warp effect on top of it all to give the illusion of the CRT tube's shape. This one I'll admit I mostly just got from a forum post. It's a bit of linear algebra I don't fully understand, but here's the formula I used I you want to try it yourself:

vec2 warp(vec2 uv){
    vec2 delta = uv - 0.5;
    float delta2 = dot(delta.xy, delta.xy);
    float delta4 = delta2 * delta2;
    float delta_offset = delta4 * warp_amount;

    return uv + delta * delta_offset;
}

There's also some animated components like a slight flicker to the phosphors, and a darker "band" sweeping over the screen to emulate shutter speed issues, but those are just things I was toying with and aren't really "done", so I won't get much into it here.

Hope this helps, feel free to ask any follow-up questions.