Hi Pauli O,
Could you take a look at this question in the link below and give your comments, I did not get any answer yet.
I also posted the same in the feedback for current release and latest insider build 18941.
It seems that people have been complaining about this issue for a long time, but there was never an official fix or a clear explanation behind the drive duplicate in file explorer, MS is ignoring the feedback and complaints.
https://answers.microsoft.com/en-us/windows/forum/all/windows-10-1903-or-higher-duplicate-usb-devices/dfdb015c-8bc5-46f0-923c-cfdf8bfd7b4f
There is also an alternative workaround in online threads beside the one described in my question.
Adding the entry below in the registry seems to do the trick too.
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\NonEnum
.Create a new DWORD (32-bit) value named {F5FB2C77-0E2F-4A16-A381-3E560C68BC83}
.Set the data for {F5FB2C77-0E2F-4A16-A381-3E560C68BC83} to 1
I don't understand why MS is ignoring this annoying issue, also every update gets rid of the temporary workaround (either one) restoring the registry to the original bug.
The duplicate happens not just for USB drives, also in some cases for drives connected with eSATA,
(IE: WD MyBook).