I can't be sure, but looking at your last video it seems that the front panel acts as a shield for the main board. As you pull it away the noise increases, but if you pull away a shield you could expect something similar to happen. Why do you think that removing the cabinet's conductive paint would improve this situation? I'm probably missing something, but I'm not convinced these are related.
1. Conductive paint has cracked and can break off.
2. Each zone should be shielded/isolated one from another, i.e. PSU, DC/DC adapater, mainboar, from panel, etc... (See the DS2072 teardonw as good example). In the SDS7102 due to its iternal construction is very difficult to achieve this.
3. Do not forget the screen, I'm not willing to spend more money on the material needed to shield it properly.
I used a aluminum foil as a substitute using an external monitor.
"I can't be sure, but looking at your last video it seems that the front panel acts as a shield for the main board. As you pull it away the noise increases, but if you pull away a shield you could expect something similar to happen."
Yes, but this panel attenuating the field generated by the DC/DC behind it, in fact that is the predominant noise when removing it. However, the shielding (including the aluminum foil) not eliminates or attenuates the common mode noise "radiated" by the connector that joins the adapter board with the mainboard. For all this and the above exposed (1,2 and 3) I decided remove the conductive paint.