Try to increase near plane and decrease far plane as much as possible to limit problems with z-fighting.
If it’s not enough, you can use the zOffset property of the material to mitigate the artefacts.
You could also try a logarithmic depth buffer Logarithmic Depth Buffer | Babylon.js Documentation Didn’t have much luck with that myself, but probably doesn’t hurt to try. Last time i had this problem, the only thing that solved it was to get the 3d artist to move the meshes a tiny bit more apart.