I just had exactly the same thing happen to me when I was trying to set the Vive Cosmos up on my work computer. I was using an administrator account and running Viveport as an administrator, but when I went to device setup I got the 7-Zip "The requested operation requires elevation" error.
I solved it by first running the Viveport desktop app as an administrator, then ignoring the device setup menu and instead going directly to the folder with the setup files and running the "App_Launchers_ViveCosmosSetupP2CHS.exe" file as administrator, which launched the device setup properly.
On my computer this folder was at: C:\Program Files (x86)\VIVE\Updater\Temp\com.htc.windows.oobe.launchers.1613717580769\assets
I was also able to find it by going to C:\Program Files (x86) and searching for "ViveCosmosSetup".
