FYI, the foam used to ship the KBDFans 5* case works great to dampen the metallic ping of the case : r/MechanicalKeyboards
Foam - An Overview
Glorious Keyboard Carrying Case, For GMMK Pro and 75% Keyboards, Oxford Exterior, Low Profile Carrying Handle, Keyboard Pull Out Strap, Interior Mesh Pocket, Eva Foam Molded Case | GLO-ACC-KBCASE Buy, Best Price