The reality is that these do work, people just run into various issues that take a while to debug. For example on some Linux installs brltty or modemmanger can grab the port for a while before releasing it to other uses.
Often you need to add a user to the dialout group or similar (as you would for any Arduino)
It’s possible you’ll have an easier time with other hardware, but not guaranteed. The issues you are facing now are almost certainly solvable by someone familiar with Linux issues.
One useful thing to check would be the output of lsusb with and without it connected. Also note that some loaded sketches could make it not be a CDC/ACM serial device at all - there’s a way to force it to stay in bootloader mode which will, don’t know off the top of my head what it is.
You may want to pursue this on Arduino-related forums as what you are facing are Leonardo/Micro type challenges, not really LoRa challenges.