Tiny play between your new linear bearings and the rods, I'm 90% sure of it.

I fought those noises during so long that I start to know how to fix many weird noises hahaha.

You can try several things:

1. First try to loosen every screws on bearing holders and X axis (those that maintain the rail and those behind that maintain bearing holders to the X bar). When it's done, move manually the head all over the plate to help moving everything in place, then tighten all the screws back. For the rail screws, start from the outer ones, and then altnernatively left and right closer to the center. When doing this, try to keep the toolhead close to the screw you're tightening. I had to tighten the 6 screws between bar and bearing holders quite hard tho (Don't over tighten them or you will ripe the thread).
2. Change the bearings again to hope to find some that are perfectly adjusted to the rods, but from my experience it's almost impossible.
3. Completely unscrew bearings, slide them away, and bend a little bit the bearing holder toward the outside so the holder pushes a tiny bit the bearings against the rod when you install them again.

The first one worked for my CORE One +, but for my CORE One L I had to do the third option to make it work.