My desktop PC is quiet in idle and even while gaming (absolutely most of the time, depending on how many things are going on): The AMD X3D CPU is all cores undervolted using BIOS's PBO feature + a Macho CPU cooler, and a dedicated GPU is at -45-50% power, all in an open case. Only if the CPU utilizes like more than 4 threads, do I hear the fan.
If you need a room with 0 guaranteed noise, where also the water cooling fans would have to be outside, then this makes sense.
The Akasa Pascal case offering complete water and dust proofing with fanless cooling houses an ASRock X600TM-ITX motherboard and may be equipped with Ryzen 5 9600X or Ryzen 7 9700X APU options. The motherboard supports up to 96 GB DDR5-6400 RAM and 16 TB NVMe storage plus 16 TB SATA storage.