You spent an hour painting your model for the AMS, the slicer says it needs repair, and every repair tool you try hands back a fixed mesh with all the color data gone. That happens because most repair tools rebuild the mesh from scratch — and Bambu Studio stores paint assignments on each individual triangle of the original mesh.
Voxel-based repair (Windows 3D Builder, Netfabb-style services) guarantees a watertight result by replacing your mesh entirely. New triangles, no paint. Ferdelance takes the opposite approach: it repairs the triangles you have — welding, capping, splitting — and carries each triangle's color attributes through every step.