Geeze, that’s extremely frustrating… they really switched up the headaches between v1 and v2. I’m sorry I couldn’t be more help! Hopefully you can find a software solution to get it going.
I don’t mean to repeat troubleshooting you’ve already done with the python script, apologies in advance if this is stuff you’ve already done. If it’s erroring immediately, you may want to double check that you have pyUSB in place and UDEV rules to get access to the device if you’re not running the script as root.
edit: You may also need to check that your Vendor ID and Product ID match what the script was written for, given that there seem to be some different iterations of Lian Li’s hardware just in general.