After moving I found a neat little space to put my Printer:
And to prevent it being like a little echo chamber I added the sound dampening foam in the back, that already helped a lot.
But vibrations were still a big problem, so I applied the cheap fix a lot of people recommended on reddit: the concrete plate at the bottom:
The Weight and structure of the plate pretty much cancels out the vibrations induced into the shelve. And to prevent damage to the furniture I put a piece of cardboard underneath the plate. Now the only noise I hear are the printer itself. It started rattling recently, probably because something is getting lose… But otherwise it still remains pretty much silent when it runs in stealth mode.
Also when I close the door, the top half of the printer is hidden and only the base peaks out. I might get a problem when I use the maximum height of the print area, but even then I could just leave the door open for the duration of the print.
I’m especially happy with the mounted power outlets.