Modifying the Phase bar in David Bacci's PowerBI Deneb Gantt chart

Question

I have been playing around David Bacci's Gantt chart for Deneb to show a company project schedule.

Instead of showing the "phase" as a continuous bar from starting date of first task to end date of last task, I want the "phase" split into separate bars only appearing when there are ongoing underlying tasks.

Red areas should be transparent or bar should end and restart

So far I have not been successful in modifying this (with very limited knowledge to Vega and help from AI).

My first priority is to understand if this would require a large change to the original code, or should it be relatively simple?