The classic choice would be fractal design’s node 304 which fits six 3.5" drive in an ITX form factor. There’s also Silverstone’s CS381 which while being larger can fit eight hotswappable 3.5" drives and a micro atx motherboard.
Even if you go ITX you don’t have to feel limited by the lack of PCIe slots. Since m.2 uses the PCIe protocol it’s very easy to adapt it to your needs such as to an additional PCIe 4x slot. There are even m.2 10GBe cards in both intel and Realtek flavors.
Side question, what coral TPU do you have because it was my understanding that they use m.2, mini pcie, or USB and not the full size pcie slot?