Definitely not unique to you. I had tried everything in this thread to no avail. As soon as I let the WinUSB drivers install, the updater could see my Helix Rack again.
Without the "WinUSB" drivers, there's a random device that appears to the computer as "Msg Pipe" but doesn't have a driver. With these drivers installed, that same device shows up as "Helix Rack" and the updater can see the unit.
Edit: Interestingly, looking at the drivers that are installed when "WinUSB" is selected, the INF includes entries for basically every piece of Helix hardware. The architectural changes in 2.80 are clear since the Helix Drivers actually installs two packages simultaneously now, 1.92 (which works for any Helix unit pre 2.8) and 1.93 (which obviously applies to 2.80). To Windows a 2.80 Helix is a completely different piece of hardware than any earlier version. It also enumerates an extra device as mentioned above that the WinUSB drivers apply to. Not sure if this is for sending keyboard inputs to the PC, or perhaps a new way for L6 software to talk to the Helix, but it's clearly necessary for the update to complete.
The installer is a tiny bit misleading (imho) in that it can lead you to believe you don't need the WinUSB driver if you have a rack/floor/etc.