This is a demo tutorial. While there is no step-by-step commentary available (yet), the live demo below is fully functional. Feel free to open it for full source code.
This demo shows how we can use custom bullets with path set and "property fields" to bind each individual color to data.
See the Pen amCharts 4: SVG bullets with custom path and colors by amCharts team (@amcharts) on CodePen.24419