How to install powershell modules within a docker container off the mcr.microsoft.com/powershell image?

Question

Please, observe:

C:\> docker run -it mcr.microsoft.com/powershell pwsh
PowerShell 6.2.4
Copyright (c) Microsoft Corporation. All rights reserved.

https://aka.ms/pscore6-docs
Type 'help' to get help.

PS /> Get-PSRepository
WARNING: Unable to find module repositories.
PS /> Get-PackageProvider

Name                     Version          DynamicOptions
----                     -------          --------------
NuGet                    3.0.0.1          Destination, ExcludeVersion, Scope, SkipDependencies, Headers, FilterOnTag, Contains, AllowPrereleaseVersions, ConfigFile, SkipVali…
PowerShellGet            2.1.3.0          PackageManagementProvider, Type, Scope, AllowClobber, SkipPublisherCheck, InstallUpdate, NoPathUpdate, AllowPrereleaseVersions, Fil…

PS /> Register-PSRepository -Default
PS /> Get-PSRepository
WARNING: Unable to find module repositories.
PS /> $env:PSModulePath
/root/.local/share/powershell/Modules:/usr/local/share/powershell/Modules:/opt/microsoft/powershell/6/Modules
PS />

So, there is no PS repositories. OK, I run Register-PSRepository -Default - it does not fail. But it also does nothing - I still have no PS repositories.

Other people have the same issue, but I did not understand how they resolved it. What blows my mind is that it is microsoft's powershell image that does not work.

What am I missing?

EDIT 1

Please, allow me to clarify the acceptance criteria for an answer. If your answer shows how one can run docker run -it mcr.microsoft.com/powershell pwsh and then Get-PSRepository - you hit the mark and get the points.

Answer 1

The answer for me seems to be to run this after I connect to VPN

Get-NetIPInterface -InterfaceAlias "vEthernet (WSL)" | Set-NetIPInterface -InterfaceMetric 1
Get-NetAdapter | Where-Object {$_.InterfaceDescription -Match "Cisco AnyConnect"} | Set-NetIPInterface -InterfaceMetric 6000

I found this at https://sysblog.dk/?p=254

If you would like to "set it and forget it", follow these instructions for setting up a scheduled task trigger.