I was able to get this working in Mac OS 26.1 Tahoe on a Mac mini M2. Here's what I had to do:
Start the Mac in Recovery mode. This took probably 5 minutes
Power off your Mac
Hold down the power button until you're prompted to select either your boot drive or Options
Click Options
Wait a bit while it scans your disk
In the top menu go to Utilities...Startup Security Utility
Select the system on which you want to install the Driver. If the disk is encrypted with FileVault, click Unlock, enter the password, and then click Unlock.
Click Security Policy, choose Reduced Security and check the option to allow user management of kernel extensions from identified developers
Click OK. Enter the password for your account and click OK.
Restart your Mac from Apple menu
Download the Line6 Driver here: https://line6.com/software/readeula.html?rid=11477
Install the driver
Run the following from a Terminal window (you can press CMD + Spacebar to search for Terminal if needed):
sudo kextload /Library/Extensions/Line6AudioUniversal.kext
Reboot the Mac
I hope that helps!