Nice build
@casual_audio_nerd!
One word regarding earthing/safety:
These modules and SMPS are class II, so you should not need safety earth, but then you should maintain class II throughout the assembly which in that case implies isolating the power wires (from the enclosure as well as other cables) with a second layer such as some electrical plastic tubing (not nice to look at, but effective and affordable).
If you prefer to rely on the safety earth, then you should make sure it is effective on the entirety of the enclosure, which first implies making sure the wire is appropriately connected to the lower part of the enclosure (sanding if necessary, toothed washer biting the enclosure, blocking nut, etc.), and that all enclosure parts are adequately connected together (sanding again).
There is also a small thermal "optimization" that can be done for the SMPS...