[Coder-san]

If you could fix the white border it would be much better.

Actually there is no white border.
It seems like it has white border because it is in black background.

It's because of the 3d renders you are using, enable alpha channel in the render setup or similar.
If the 3d animation program is giving this animated GIF output, then enabling alpha channel should do the trick.
But if you exported frames and then compiled animated GIF via photoshop or something, then you need to export frames as PNG.