This is old, but still relevant since I encountered the problem today.
There are a couple caveats though:
Please keep in mind that this solution does not support
auto-updating, you'll need to manually keep track of the updated
and/or put in place you own update mechanism.
Depending on your organization's settings, you also might need to have access to Powershell (non-admin) and the
Appx module.
The following website allows to get direct downloads links for Microsoft store packages and their dependencies: https://store.rg-adguard.net/
Juste paste the Microsoft store URL into the website, click the checkmark on the right, and you'll get a list of links.
Now, you will want to download one of each listed package for your computer architecture (most are x64 these days, but you might need the arm/arm64 ones)
So, for whiteboard at the time of writing, you will need to download the following packages (I recommend to download them all into a new folder):
- Microsoft.NET.Native.Framework.2.2_2.2.29512.0_x64__8wekyb3d8bbwe.Appx
- Microsoft.VCLibs.140.00_14.0.30035.0_x64__8wekyb3d8bbwe.Appx
- Microsoft.Whiteboard_21.10405.5658.0_neutral___8wekyb3d8bbwe.AppxBundle
Now we come to the installation.
If you're "lucky", you'll just have to double click on each packages, and for each of them click install.
If windows asks you what to do with it or you get a message that the application was disabled, open a powershell prompt in the folder you downloaded the packages in.
Assuming the only files in the folder to be the packages, the following will install them all
Get-ChildItems | Add-AppxPackage
This should install all of the packages.