Fireworks creator based on two things: Bézier curve and geometry nodes.

Curve is used as path for rocket. Movement is controlled by Timeline and two properties (ignition frame and explosion frame).

Particles (explosions and sparks) are driven by simple physics. They have basic properties like density, speed, air drag, gravity and size. Every kind of particles has separate settings.

Color and brightness depend on assigned materials. You can create your own.

You will get .blend file with ready to use firework. You will have to append it to your project and make adjustments. I show how to in movie below.

Known issues:

• need to refresh cache after any change > This creator uses Simulation Zone node which can't start working from middle of action. Just go to first frame and play animation.
  
• occasionally disappearing particles > It looks like a Blender's fault with cache. To fix just save the file and reopen it.
  
• occasionally problems with motion blur > It looks like a Blender's fault. I don't know solution for this.
  
• sparks have large impact on playback animation framerate > Before final render use low Density for sparks.
• weired colors on Blender 3.6 > Sample firework from purchased file was created on Blender 4.0 which uses new color manager AgX, which produces less saturated colors. Also Filmic used in 3.6 has tendency to oversaturate bright surfaces. Go to shader editor and decrease Emission strength and also colors saturation.