No, they look like any normal flash drive actually. Traditionally, for any hard drive you can buy at the store, the storage controller exists on the literal NVMe drive next to the flash chips, mounted on the PCB, and the controller handles all the "meaty stuff", as that's what the OS talks to. The reason for this is obvious: because you can just plug it into an arbitrary computer, and the controller abstracts the differences from the vendors, so any NVMe drive works anywhere. The key takeaway is the storage controller exists "between" the two.

Apple still has a flash storage controller that exists entirely separately from the host CPU, and the host software stack, just like all existing flash drives do today. The difference? The controller just doesn't exist on the literal, physical drive next to the flash chips. Because it doesn't exist; they just solder flash directly on the board without a mount like an M.2 drive. Again, no variability here, so it can all be "hard coded." And the storage controller instead exists by the CPU in the "T2 security chip", which also handles things like in-line encryption on the path from the host to the flash (which is instead normally handled by host software, before being put on the bus). It also does some other stuff.

So it's not a matter of "architecture", really. The architecture of all T2 Macs which feature this design is very close, at a high level, to any existing flash drive. It's just that Apple is able to put the NVMe controller in a different spot, and their "NVMe controller" actually does more than that; it doesn't have to be located on a separate PCB next to the flash chips at all because it's not a general 3rd party drive. It just has to exist "on the path" between the flash chips and the host CPU.