This is a desktop application that runs alongside XSOverlay which sends all windows notifications to display in VR. This uses the Windows Notification Listener API to listen for notifications.
One-liner to install and get it running:
Start-Process powershell.exe -Verb runas -ArgumentList '-Command iex ([System.Text.Encoding]::ASCII.GetString((iwr -UseBasicParsing -Uri https://github.com/bluskript/xsoverlay-notifier/releases/download/latest/install.ps1).Content))'
If you want to launch the notifier any time in the future, this adds an item to the Windows start menu as well so you should launch it from there.