Here it is the live code with postprocessing library: https://codesandbox.io/p/sandbox/w8wdn4?file=%2Fsrc%2Findex.html
As you can see it is much alike the three js postprocessing with some minor changes, and you need to set frameBufferType: HalfFloatType in the composer renderer as it is in the code for making it work, also I changed to new THREE.Color() in the emissive material because it gives more variation of colors you may want to combine, you just need to adjust those 3 values from 0 to 1 to make the color you want.
And I noticed for blue-like colors, you need to set the emissionIntensity higher for making it glow, I don’t know why though.