The original poster in this thread appears to be using the same software as you, and they posted quite a bit of detail on locating the correct device.
Try /dev/ttyUSBn where n is usually a changing number from reboot to reboot (or even from unplug to plug).
If it’s there, you should be able to list it with: ls /dev/ttyUSB*
On my Ubuntu 22 system, I don’t have anything matching while my digirig lite is plugged in. Perhaps because I have a digirig lite.