In this case I'm using Windows 11 indeed, namely the Pro version.
Apparently the drivers that Zadig gives are indeed in a per-port basis in this case. Now that I located the device and installed a new WinUSB driver via Zadig, I can use one of the front ports that didn't work before.
Unfortunately, this doesn't change the known outcome once I attempt to load the Agatti loader, even when I'm resetting the device and sending it back to EDL mode after each failure:
Code:
Sending 0014d0e100000000_d40eee56f3194665_FHPRG.bin 100% Ok
Waiting for Firehose... No response, poking...
Could not write device