Using Mesh instead of Group is bad practise to change opacity of an 3DObject?

Hello thank you for your reply. My question is linked to my other post.
I want to make a dynamic background where multiples 3dObject fade in and fade out randomly.
Kinda like this
I try using delay to make the animation look desync but it always play at the same time for all 3dObject.
I came across the library gsap with his timeline object but it can’t modify the opacity of a 3dObject with one property, I have to traverse all the mesh child and change their material opacity.
Maybe your use of MeshPortalMaterial and ScreenQuad can help me with gsap