Pick the Engine building block first, then adapt its closest official example with find-examples:

• Particle systems: the particlesystem component (graphics/particles-* examples).
• Custom shading on existing surfaces: StandardMaterial chunk overrides (override-shader-chunks), or a ShaderMaterial when the effect needs its own shader pair.
• Procedural or per-frame geometry: a runtime-updated Mesh on a render component (graphics/mesh-* examples), or WideLineRenderer for lines with width.
• Full-screen effects: CameraFrame (light-scene).
• Gaussian splat effects: the shipped gsplat scripts (reuse-scripts).

• CurveSet takes one key array per channel. A flattened array type-checks, then fails at texture upload.
• Create emitters and meshes at load and reuse them. Fire an emitter with reset() then play(); one-shots use loop: false.
• The first use of a shader stalls a frame. Render each effect once behind a loading screen.
• Animate values with setParameter, not a per-frame material.update().
• A lit material on a custom mesh needs normals; otherwise use an unlit material.

Trigger each effect through the app's real inputs, and confirm repeated triggers keep entity counts stable.