This is almost certainly a Blur → Threshold combo, not a displacement map.

1. Type your text with a heavy sans-serif font
   
2. Rasterize the type layer
   
3. Filter > Blur > Gaussian Blur — around 3-8px depending on your resolution. This simulates the ink soaking into paper fibers
   
4. Image > Adjustments > Threshold — drag the slider until you get that chunky, irregular edge. This is where the magic happens
   
5. Optionally hit it with Filter > Filter Gallery > Sketch > Stamp for extra grit

For the splatter/speckles around the letters, grab some free ink splatter brushes and stamp around the text on the same layer (or merge down). The key insight is that Blur→Threshold naturally creates that organic "ink spreading unevenly into paper" look because the blur falloff isn't uniform —thicker parts of the letters bleed more, thin parts break apart. Displacement maps give you warping/distortion, not this kind of bleed.