Nice! I totally get it. Just some advice: if you build something for in your closet, make sure it stands on thick rubber feet / mat. Or make a cage suspend from elastic binders. Anything to avoid the vibrations to go into the wood/metal of the closet.

It’s how I have my NAS, also in a closet (next to Tom Cruise)

Some sound isolation pads (soft foam with pointy bits) around it are also an option. Just make sure it gets enough air for cooling. If you need more fresh air from outside, use the silent Noctua fans, they have less air displacement but really are very silent.