Making the renderer is an iterative process. I started with just drawing lines, then progressively added all the different effects (bloom, chromatic aberration, etc…). You can get a renderer in a week of full time work, but then there are endless improvements you can make. Even today the renderer of PewPew Live could be improved in a lot of ways.
It’s totally doable to do a 2D renderer with ray tracing lights. 2D simplifies many many things!