As you well say Cassius the problem was the camera focus distance.
For all those who get here for an answer, I would suggest if you’re using a similar approach with a 3d scene and particles, adjusting your world size settings in your 3D Element layer before to start animating your camera.
Taking your camera settings as a reference for “world size dimensions” between 3d layers and particles will ensure expected results.
I’ll might come back posting a final breakdown If I get some free time.
Thanks you both for the answers!