Three.js r184: Severe First-Frame Stutter with a Large Number of Meshes

### Description I’m working on a project that converts SVG files into meshes using my own fast algorithm. For large SVG files, the conversion can produce thousands of meshes. Each mesh currently uses a basic PBR material implemented with TSL. The issue is that after adding these meshes to the scene, the first render can take around **15 seconds**. The delay increases as the mesh count grows, while subsequent frames are much faster. However, after the first frame has completed, the overall frame rate returns to an acceptable level. Although the performance is still worse than WebGL, it is acceptable for my use case. ============= Also, switching to a different CanvasTarget, changing the scene’s envMap, or adding lights can all cause stalls lasting tens of seconds. ### Reproduction steps 1.Create a WebGPU renderer. 2.Create 1,000 meshes using a TSL PBR node material. 3.Execute the render. ### Code ```js // code goes here ``` ### Live example [example](https://jsfiddle.net/mn9swobk/11/) ### Screenshots _No response_ ### Version r184 ### Device Desktop ### Browser _No response_ ### OS _No response_